Key error in viewable._models[mref] if pn.Card is used with ChatFeed and Bootstrap

[krlng]

TLDR:
I think this is a kind of niche issue. I only discovered it in the combination of Bootstrap and a pn.Card element within a ChatFeed. How ever I think it is important to fix it, as it looks to me that something deep in the system does not align.

My Scenario:
I am using AutoGen for a Multi-Agent-Chat setup. In this setup, a user asks a question, many LLM calls will happen under the hood and a final answer is returned. I would like to show those many intermediate LLM calls in a collapsible and somehow differently styled box, which is why I use the pn.Card element. This does work, how ever it breaks as soon as I put it into a Bootstrap template as explained below.

ALL software version info

panel 1.3.6
param 1.13.0
(More info that is probably not relevant: python 3.10, MacOS, usage in Notebook, Firefox)

Description of expected behavior and the observed behavior

Complete, minimal, self-contained example code that reproduces the issue

import panel as pn
from panel.chat import ChatInterface, ChatMessage


active_wip = None
def ask_question(contents, user=None, instance=None):
    chat_ui.append(ChatMessage(contents, user="user"))
    active_wip = pn.chat.ChatFeed(
        scroll=True,
        height=300,
        callback_exception="raise",
        height_policy="fixed",
        card_params = dict(
            collapsible=True,
            collapsed=True,
            title="Work in Progress", background = "red"),
        styles={"background": "WhiteSmoke"}, 
    )

    # This works in combination with BootstrapTemplate
    # chat_ui.append(active_wip)

    # This does not work in combination with BootstrapTemplate
    chat_ui.append(pn.Card(active_wip, styles={"background": "WhiteSmoke"}, title="Work in Progress"))
    for word in contents.split(" "):
        active_wip.append(ChatMessage(word))
    chat_ui.append(ChatMessage(contents.capitalize(), user="ai"))


def setup_chat_interface():
    text_input = pn.widgets.TextAreaInput(
        placeholder="Bitte geben Sie Ihre Nachricht hier ein...",
        rows=3,
        max_rows=5,
        auto_grow=True,
        value="Was waren die wichtigsten Trends gestern?",
    )
    
    return ChatInterface(
        callback=lambda *args: ask_question(*args),
        user="User",
        callback_exception="raise",
        show_clear=False,
        show_send=False,
        show_undo=False,
        show_rerun=False,
        widgets=[
            text_input,
        ],
        button_properties={
            "Submit": {"callback": lambda i, e: ask_question(text_input.value), "icon": "send"}
        },
    )


chat_ui = setup_chat_interface()
# This always works
# pn.serve(chat_ui)

app_bootstrap = pn.template.BootstrapTemplate(title='Test')
app_bootstrap.main.append(chat_ui)

# This only works if no pn.Card is used (see above)
pn.serve(app_bootstrap)

Stack traceback and/or browser JavaScript console output

ERROR:bokeh.server.protocol_handler:error handling message
 message: Message 'PATCH-DOC' content: {'events': [{'kind': 'MessageSent', 'msg_type': 'bokeh_event', 'msg_data': {'type': 'event', 'name': 'button_click', 'values': {'type': 'map', 'entries': [['model', {'id': 'p17078'}]]}}}]} 
 error: KeyError('p17044')
Traceback (most recent call last):
  File "/Users/nicokreiling/Library/Caches/pypoetry/virtualenvs/trendllm-byt5rvl_-py3.10/lib/python3.10/site-packages/bokeh/server/protocol_handler.py", line 97, in handle
    work = await handler(message, connection)
  File "/Users/nicokreiling/Library/Caches/pypoetry/virtualenvs/trendllm-byt5rvl_-py3.10/lib/python3.10/site-packages/bokeh/server/session.py", line 94, in _needs_document_lock_wrapper
    result = func(self, *args, **kwargs)
  File "/Users/nicokreiling/Library/Caches/pypoetry/virtualenvs/trendllm-byt5rvl_-py3.10/lib/python3.10/site-packages/bokeh/server/session.py", line 286, in _handle_patch
    message.apply_to_document(self.document, self)
  File "/Users/nicokreiling/Library/Caches/pypoetry/virtualenvs/trendllm-byt5rvl_-py3.10/lib/python3.10/site-packages/bokeh/protocol/messages/patch_doc.py", line 104, in apply_to_document
    invoke_with_curdoc(doc, lambda: doc.apply_json_patch(self.payload, setter=setter))
  File "/Users/nicokreiling/Library/Caches/pypoetry/virtualenvs/trendllm-byt5rvl_-py3.10/lib/python3.10/site-packages/bokeh/document/callbacks.py", line 443, in invoke_with_curdoc
    return f()
  File "/Users/nicokreiling/Library/Caches/pypoetry/virtualenvs/trendllm-byt5rvl_-py3.10/lib/python3.10/site-packages/bokeh/protocol/messages/patch_doc.py", line 104, in <lambda>
    invoke_with_curdoc(doc, lambda: doc.apply_json_patch(self.payload, setter=setter))
  File "/Users/nicokreiling/Library/Caches/pypoetry/virtualenvs/trendllm-byt5rvl_-py3.10/lib/python3.10/site-packages/bokeh/document/document.py", line 391, in apply_json_patch
    DocumentPatchedEvent.handle_event(self, event, setter)
  File "/Users/nicokreiling/Library/Caches/pypoetry/virtualenvs/trendllm-byt5rvl_-py3.10/lib/python3.10/site-packages/bokeh/document/events.py", line 245, in handle_event
    event_cls._handle_event(doc, event)
  File "/Users/nicokreiling/Library/Caches/pypoetry/virtualenvs/trendllm-byt5rvl_-py3.10/lib/python3.10/site-packages/bokeh/document/events.py", line 280, in _handle_event
    cb(event.msg_data)
  File "/Users/nicokreiling/Library/Caches/pypoetry/virtualenvs/trendllm-byt5rvl_-py3.10/lib/python3.10/site-packages/bokeh/document/callbacks.py", line 390, in trigger_event
    model._trigger_event(event)
  File "/Users/nicokreiling/Library/Caches/pypoetry/virtualenvs/trendllm-byt5rvl_-py3.10/lib/python3.10/site-packages/bokeh/util/callback_manager.py", line 113, in _trigger_event
    self.document.callbacks.notify_event(cast(Model, self), event, invoke)
  File "/Users/nicokreiling/Library/Caches/pypoetry/virtualenvs/trendllm-byt5rvl_-py3.10/lib/python3.10/site-packages/bokeh/document/callbacks.py", line 260, in notify_event
    invoke_with_curdoc(doc, callback_invoker)
  File "/Users/nicokreiling/Library/Caches/pypoetry/virtualenvs/trendllm-byt5rvl_-py3.10/lib/python3.10/site-packages/bokeh/document/callbacks.py", line 443, in invoke_with_curdoc
    return f()
  File "/Users/nicokreiling/Library/Caches/pypoetry/virtualenvs/trendllm-byt5rvl_-py3.10/lib/python3.10/site-packages/bokeh/util/callback_manager.py", line 109, in invoke
    cast(EventCallbackWithEvent, callback)(event)
  File "/Users/nicokreiling/Library/Caches/pypoetry/virtualenvs/trendllm-byt5rvl_-py3.10/lib/python3.10/site-packages/panel/reactive.py", line 494, in _server_event
    self._comm_event(doc, event)
  File "/Users/nicokreiling/Library/Caches/pypoetry/virtualenvs/trendllm-byt5rvl_-py3.10/lib/python3.10/site-packages/panel/reactive.py", line 481, in _comm_event
    state._handle_exception(e)
  File "/Users/nicokreiling/Library/Caches/pypoetry/virtualenvs/trendllm-byt5rvl_-py3.10/lib/python3.10/site-packages/panel/io/state.py", line 442, in _handle_exception
    raise exception
  File "/Users/nicokreiling/Library/Caches/pypoetry/virtualenvs/trendllm-byt5rvl_-py3.10/lib/python3.10/site-packages/panel/reactive.py", line 479, in _comm_event
    self._process_bokeh_event(doc, event)
  File "/Users/nicokreiling/Library/Caches/pypoetry/virtualenvs/trendllm-byt5rvl_-py3.10/lib/python3.10/site-packages/panel/reactive.py", line 416, in _process_bokeh_event
    self._process_event(event)
  File "/Users/nicokreiling/Library/Caches/pypoetry/virtualenvs/trendllm-byt5rvl_-py3.10/lib/python3.10/site-packages/panel/widgets/button.py", line 247, in _process_event
    self.clicks += 1
  File "/Users/nicokreiling/Library/Caches/pypoetry/virtualenvs/trendllm-byt5rvl_-py3.10/lib/python3.10/site-packages/param/parameterized.py", line 525, in _f
    instance_param.__set__(obj, val)
  File "/Users/nicokreiling/Library/Caches/pypoetry/virtualenvs/trendllm-byt5rvl_-py3.10/lib/python3.10/site-packages/param/parameterized.py", line 527, in _f
    return f(self, obj, val)
  File "/Users/nicokreiling/Library/Caches/pypoetry/virtualenvs/trendllm-byt5rvl_-py3.10/lib/python3.10/site-packages/param/parameters.py", line 542, in __set__
    super().__set__(obj,val)
  File "/Users/nicokreiling/Library/Caches/pypoetry/virtualenvs/trendllm-byt5rvl_-py3.10/lib/python3.10/site-packages/param/parameterized.py", line 527, in _f
    return f(self, obj, val)
  File "/Users/nicokreiling/Library/Caches/pypoetry/virtualenvs/trendllm-byt5rvl_-py3.10/lib/python3.10/site-packages/param/parameterized.py", line 1545, in __set__
    obj.param._call_watcher(watcher, event)
  File "/Users/nicokreiling/Library/Caches/pypoetry/virtualenvs/trendllm-byt5rvl_-py3.10/lib/python3.10/site-packages/param/parameterized.py", line 2486, in _call_watcher
    self_._execute_watcher(watcher, (event,))
  File "/Users/nicokreiling/Library/Caches/pypoetry/virtualenvs/trendllm-byt5rvl_-py3.10/lib/python3.10/site-packages/param/parameterized.py", line 2468, in _execute_watcher
    watcher.fn(*args, **kwargs)
  File "/var/folders/md/lg_vw48n7db289y9xlnzcbd00000gn/T/ipykernel_91544/1256256118.py", line 51, in <lambda>
    "Submit": {"callback": lambda i, e: ask_question(text_input.value), "icon": "send"}
  File "/var/folders/md/lg_vw48n7db289y9xlnzcbd00000gn/T/ipykernel_91544/1256256118.py", line 24, in ask_question
    chat_ui.append(pn.Card(active_wip, styles={"background": "WhiteSmoke"}, title="Work in Progress"))
  File "/Users/nicokreiling/Library/Caches/pypoetry/virtualenvs/trendllm-byt5rvl_-py3.10/lib/python3.10/site-packages/panel/layout/base.py", line 448, in append
    self.objects = new_objects
  File "/Users/nicokreiling/Library/Caches/pypoetry/virtualenvs/trendllm-byt5rvl_-py3.10/lib/python3.10/site-packages/param/parameterized.py", line 525, in _f
    instance_param.__set__(obj, val)
  File "/Users/nicokreiling/Library/Caches/pypoetry/virtualenvs/trendllm-byt5rvl_-py3.10/lib/python3.10/site-packages/param/parameterized.py", line 527, in _f
    return f(self, obj, val)
  File "/Users/nicokreiling/Library/Caches/pypoetry/virtualenvs/trendllm-byt5rvl_-py3.10/lib/python3.10/site-packages/param/parameterized.py", line 1545, in __set__
    obj.param._call_watcher(watcher, event)
  File "/Users/nicokreiling/Library/Caches/pypoetry/virtualenvs/trendllm-byt5rvl_-py3.10/lib/python3.10/site-packages/param/parameterized.py", line 2486, in _call_watcher
    self_._execute_watcher(watcher, (event,))
  File "/Users/nicokreiling/Library/Caches/pypoetry/virtualenvs/trendllm-byt5rvl_-py3.10/lib/python3.10/site-packages/param/parameterized.py", line 2468, in _execute_watcher
    watcher.fn(*args, **kwargs)
  File "/Users/nicokreiling/Library/Caches/pypoetry/virtualenvs/trendllm-byt5rvl_-py3.10/lib/python3.10/site-packages/panel/reactive.py", line 676, in link_cb
    setattr(target, links[event.name], event.new)
  File "/Users/nicokreiling/Library/Caches/pypoetry/virtualenvs/trendllm-byt5rvl_-py3.10/lib/python3.10/site-packages/param/parameterized.py", line 525, in _f
    instance_param.__set__(obj, val)
  File "/Users/nicokreiling/Library/Caches/pypoetry/virtualenvs/trendllm-byt5rvl_-py3.10/lib/python3.10/site-packages/param/parameterized.py", line 527, in _f
    return f(self, obj, val)
  File "/Users/nicokreiling/Library/Caches/pypoetry/virtualenvs/trendllm-byt5rvl_-py3.10/lib/python3.10/site-packages/param/parameterized.py", line 1545, in __set__
    obj.param._call_watcher(watcher, event)
  File "/Users/nicokreiling/Library/Caches/pypoetry/virtualenvs/trendllm-byt5rvl_-py3.10/lib/python3.10/site-packages/param/parameterized.py", line 2486, in _call_watcher
    self_._execute_watcher(watcher, (event,))
  File "/Users/nicokreiling/Library/Caches/pypoetry/virtualenvs/trendllm-byt5rvl_-py3.10/lib/python3.10/site-packages/param/parameterized.py", line 2468, in _execute_watcher
    watcher.fn(*args, **kwargs)
  File "/Users/nicokreiling/Library/Caches/pypoetry/virtualenvs/trendllm-byt5rvl_-py3.10/lib/python3.10/site-packages/panel/reactive.py", line 374, in _param_change
    self._apply_update(named_events, properties, model, ref)
  File "/Users/nicokreiling/Library/Caches/pypoetry/virtualenvs/trendllm-byt5rvl_-py3.10/lib/python3.10/site-packages/panel/reactive.py", line 302, in _apply_update
    self._update_model(events, msg, root, model, doc, comm)
  File "/Users/nicokreiling/Library/Caches/pypoetry/virtualenvs/trendllm-byt5rvl_-py3.10/lib/python3.10/site-packages/panel/layout/base.py", line 125, in _update_model
    state._views[ref][0]._preprocess(root, self, old_children)
  File "/Users/nicokreiling/Library/Caches/pypoetry/virtualenvs/trendllm-byt5rvl_-py3.10/lib/python3.10/site-packages/panel/viewable.py", line 598, in _preprocess
    hook(self, root, changed, old_models)
  File "/Users/nicokreiling/Library/Caches/pypoetry/virtualenvs/trendllm-byt5rvl_-py3.10/lib/python3.10/site-packages/panel/theme/base.py", line 141, in _apply_hooks
    self._reapply(changed, root, old_models, isolated=False, cache=cache, document=root.document)
  File "/Users/nicokreiling/Library/Caches/pypoetry/virtualenvs/trendllm-byt5rvl_-py3.10/lib/python3.10/site-packages/panel/theme/base.py", line 132, in _reapply
    self._apply_modifiers(o, ref, self.theme, isolated, cache, document)
  File "/Users/nicokreiling/Library/Caches/pypoetry/virtualenvs/trendllm-byt5rvl_-py3.10/lib/python3.10/site-packages/panel/theme/base.py", line 236, in _apply_modifiers
    cls._apply_params(child, mref, child_modifiers, document)
  File "/Users/nicokreiling/Library/Caches/pypoetry/virtualenvs/trendllm-byt5rvl_-py3.10/lib/python3.10/site-packages/panel/theme/base.py", line 249, in _apply_params
    model, _ = viewable._models[mref]
KeyError: 'p17044'

Screenshots or screencasts of the bug in action

Working version with pn.Card but without Bootstrap:

Working version with Bootstrap but without pn.Card: