diff --git a/docs/source/conf.py b/docs/source/conf.py
index 782273a9..28ab1406 100644
--- a/docs/source/conf.py
+++ b/docs/source/conf.py
@@ -285,6 +285,18 @@ def run(self, source_dir=None):
         nb_cache_dir = Path("../build/doctrees/nbsphinx")  # relative to build
         for notebook in nb_paths:
             nb_cache = nb_cache_dir / self.base_doc_dir / index_path / notebook.name
+
+            print()
+            print(notebook)
+            print("cache at", nb_cache, nb_cache.is_file())
+            print(
+                "diff",
+                diff_notebooks(
+                    read_notebook(notebook, on_null="empty"),
+                    read_notebook(nb_cache, on_null="empty"),
+                ),
+            )
+
             if (
                 nb_cache.is_file()
                 and "'key': 'source'"
@@ -293,11 +305,13 @@ def run(self, source_dir=None):
                     read_notebook(nb_cache, on_null="empty"),
                 ).__repr__()
             ):
+                print("COPYING CACHE")
                 shutil.copy(
                     nb_cache,
                     self.base_doc_dir / index_path / notebook.name,
                 )
             else:
+                print("COPYING NOTEBOOK")
                 shutil.copy(notebook, self.base_doc_dir / index_path / notebook.name)
 
         # Recursively go through all directories in source, documenting what is available.
@@ -312,4 +326,3 @@ def run(self, source_dir=None):
 sys.path.append(os.path.abspath("../.."))
 PackageCrawler(Path("../../src/bsk_rl/"), Path("./api_reference/")).run()
 PackageCrawler(Path("../../examples"), Path("./examples/"), filter_all=False).run()
-import nbdime