diff --git a/.github/workflows/test_full.yml b/.github/workflows/test_full.yml
index 0f977ba1..49346a25 100644
--- a/.github/workflows/test_full.yml
+++ b/.github/workflows/test_full.yml
@@ -2,14 +2,15 @@ name: Tests Full Python
 
 on:
   schedule:
-    - cron:  '4 2 * * 3'
+    - cron: "4 2 * * 3"
+  workflow_dispatch:
 
 jobs:
   Library:
     runs-on: ${{ matrix.os }}
     strategy:
       matrix:
-        python-version: ['3.7', '3.8', '3.9', '3.10']
+        python-version: ["3.7", "3.8", "3.9", "3.10"]
         os: [macos-latest, ubuntu-latest, windows-latest]
     steps:
       - uses: actions/checkout@v2
@@ -20,15 +21,15 @@ jobs:
         uses: actions/setup-python@v4
         with:
           python-version: ${{ matrix.python-version }}
-          cache: 'pip' # caching pip dependencies
+          cache: "pip" # caching pip dependencies
       - name: Install MacOS dependencies
         run: |
-            brew install libomp
+          brew install libomp
         if: ${{ matrix.os == 'macos-latest' }}
       - name: Install dependencies
         run: |
-            python -m pip install -U pip
-            pip install -r prereq.txt
+          python -m pip install -U pip
+          pip install -r prereq.txt
       - name: Test Core
         run: |
           pip install .[testing]
diff --git a/.github/workflows/test_pr.yml b/.github/workflows/test_pr.yml
index bac8905e..604617c4 100644
--- a/.github/workflows/test_pr.yml
+++ b/.github/workflows/test_pr.yml
@@ -5,14 +5,14 @@ on:
     branches: [main, release]
   pull_request:
     types: [opened, synchronize, reopened]
-
+  workflow_dispatch:
 
 jobs:
   Linter:
     runs-on: ${{ matrix.os }}
     strategy:
       matrix:
-        python-version: ['3.10']
+        python-version: ["3.10"]
         os: [ubuntu-latest]
     steps:
       - uses: actions/checkout@v2
@@ -24,19 +24,19 @@ jobs:
           python-version: ${{ matrix.python-version }}
       - name: Install dependencies
         run: |
-            pip install bandit pre-commit
+          pip install bandit pre-commit
       - name: pre-commit validation
         run: pre-commit run --all
       - name: Security checks
         run: |
-            bandit -r src/synthcity/*
+          bandit -r src/synthcity/*
 
   Library:
     needs: [Linter]
     runs-on: ${{ matrix.os }}
     strategy:
       matrix:
-        python-version: ['3.10']
+        python-version: ["3.10"]
         os: [macos-latest, ubuntu-latest, windows-latest]
     steps:
       - uses: actions/checkout@v2
@@ -47,15 +47,15 @@ jobs:
         uses: actions/setup-python@v4
         with:
           python-version: ${{ matrix.python-version }}
-          cache: 'pip' # caching pip dependencies
+          cache: "pip" # caching pip dependencies
       - name: Install MacOS dependencies
         run: |
-            brew install libomp
+          brew install libomp
         if: ${{ matrix.os == 'macos-latest' }}
       - name: Install dependencies
         run: |
-            python -m pip install -U pip
-            pip install -r prereq.txt
+          python -m pip install -U pip
+          pip install -r prereq.txt
       - name: Test Core
         run: |
           pip install .[testing]
diff --git a/.github/workflows/test_tutorials.yml b/.github/workflows/test_tutorials.yml
index c93a0c35..ba1c7a4e 100644
--- a/.github/workflows/test_tutorials.yml
+++ b/.github/workflows/test_tutorials.yml
@@ -6,8 +6,8 @@ on:
   pull_request:
     types: [opened, synchronize, reopened]
   schedule:
-    - cron:  '2 3 * * 4'
-
+    - cron: "2 3 * * 4"
+  workflow_dispatch:
 
 jobs:
   Tutorials:
@@ -25,19 +25,19 @@ jobs:
         uses: actions/setup-python@v4
         with:
           python-version: ${{ matrix.python-version }}
-          cache: 'pip' # caching pip dependencies
+          cache: "pip" # caching pip dependencies
       - name: Install MacOS dependencies
         run: |
-            brew install libomp
+          brew install libomp
         if: ${{ matrix.os == 'macos-latest' }}
       - name: Install dependencies
         run: |
-            python -m pip install -U pip
-            pip install -r prereq.txt
+          python -m pip install -U pip
+          pip install -r prereq.txt
 
-            pip install .[all]
+          pip install .[all]
 
-            python -m pip install ipykernel
-            python -m ipykernel install --user
+          python -m pip install ipykernel
+          python -m ipykernel install --user
       - name: Run the tutorials
         run: python tests/nb_eval.py --nb_dir tutorials/
diff --git a/setup.cfg b/setup.cfg
index caa59d0e..54f40eac 100644
--- a/setup.cfg
+++ b/setup.cfg
@@ -37,7 +37,7 @@ install_requires =
     pandas>=1.3,<2.0
     torch>=1.10.0,<2.0
     numpy>=1.20
-    lifelines>=0.27
+    lifelines>=0.27,!= 0.27.5
     opacus>=1.3
     decaf-synthetic-data>=0.1.6
     optuna>=3.1
diff --git a/src/synthcity/plugins/core/dataloader.py b/src/synthcity/plugins/core/dataloader.py
index 2a13424b..40bee0a8 100644
--- a/src/synthcity/plugins/core/dataloader.py
+++ b/src/synthcity/plugins/core/dataloader.py
@@ -5,6 +5,7 @@
 
 # third party
 import numpy as np
+import numpy.ma as ma
 import pandas as pd
 import PIL
 import torch
@@ -928,10 +929,21 @@ def unpack(self, as_numpy: bool = False, pad: bool = False) -> Any:
                 self.data["outcome"],
             )
         if as_numpy:
+            longest_observation_seq = max([len(seq) for seq in temporal_data])
             return (
                 np.asarray(static_data),
-                np.asarray(temporal_data),
-                np.asarray(observation_times),
+                np.asarray(pd.concat(temporal_data)),
+                # masked array to handle variable length sequences
+                ma.vstack(
+                    [
+                        ma.array(
+                            np.resize(ot, longest_observation_seq),
+                            mask=[True for i in range(len(ot))]
+                            + [False for j in range(longest_observation_seq - len(ot))],
+                        )
+                        for ot in observation_times
+                    ]
+                ),
                 np.asarray(outcome),
             )
         return (
@@ -1289,7 +1301,6 @@ def pack_raw_data(
         fill: Any = np.nan,
         seq_offset: int = 0,
     ) -> pd.DataFrame:
-
         # Temporal data: (subjects, temporal_sequence, temporal_feature)
         temporal_features = TimeSeriesDataLoader.unique_temporal_features(temporal_data)
         temporal_features, mask_features = TimeSeriesDataLoader.extract_masked_features(
diff --git a/src/synthcity/plugins/core/models/layers.py b/src/synthcity/plugins/core/models/layers.py
index 54ccf5d0..81c0578c 100644
--- a/src/synthcity/plugins/core/models/layers.py
+++ b/src/synthcity/plugins/core/models/layers.py
@@ -44,12 +44,21 @@ def forward(self, x: torch.Tensor) -> torch.Tensor:
             return x.transpose(*self.dims)
 
 
+def _get_out_features(self: nn.Module) -> int:
+    """Get the number of output features of a model."""
+    for i in reversed(range(len(self._modules["model"]))):
+        if isinstance(self._modules["model"][i], nn.Linear):
+            return self._modules["model"][i].out_features
+    raise ValueError("No linear layer found in the model.")
+
+
 @validate_arguments(config=dict(arbitrary_types_allowed=True))
 def _forward_skip_connection(
     self: nn.Module, X: torch.Tensor, *args: Any, **kwargs: Any
 ) -> torch.Tensor:
-    # if X.shape[-1] == 0:
-    #     return torch.zeros((*X.shape[:-1], self.n_units_out)).to(self.device)
+    if X.shape[-1] == 0:
+        out_shape = _get_out_features(self)
+        return torch.zeros((*X.shape[:-1], out_shape)).to(self.device)
     X = X.float().to(self.device)
     out = self._forward(X, *args, **kwargs)
     return torch.cat([out, X], dim=-1)
@@ -76,23 +85,6 @@ class Wrapper(cls):  # type: ignore
     return Wrapper
 
 
-# class GLU(nn.Module):
-#     """Gated Linear Unit (GLU)."""
-
-#     def __init__(self, activation: Union[str, nn.Module] = "sigmoid") -> None:
-#         super().__init__()
-#         if type(activation) == str:
-#             self.non_lin = get_nonlin(activation)
-#         else:
-#             self.non_lin = activation
-
-#     def forward(self, x: Tensor) -> Tensor:
-#         if x.shape[-1] % 2:
-#             raise ValueError("The last dimension of the input tensor must be even.")
-#         a, b = x.chunk(2, dim=-1)
-#         return a * self.non_lin(b)
-
-
 class GumbelSoftmax(nn.Module):
     def __init__(
         self, tau: float = 0.2, hard: bool = False, eps: float = 1e-10, dim: int = -1
diff --git a/src/synthcity/plugins/core/models/tabular_ddpm/gaussian_multinomial_diffsuion.py b/src/synthcity/plugins/core/models/tabular_ddpm/gaussian_multinomial_diffsuion.py
index 72ff5879..6414a2af 100644
--- a/src/synthcity/plugins/core/models/tabular_ddpm/gaussian_multinomial_diffsuion.py
+++ b/src/synthcity/plugins/core/models/tabular_ddpm/gaussian_multinomial_diffsuion.py
@@ -157,7 +157,10 @@ def __init__(
         self.posterior_log_variance_clipped = (
             torch.from_numpy(
                 np.log(
-                    np.append(self.posterior_variance[1], self.posterior_variance[1:])
+                    np.append(
+                        self.posterior_variance[1].cpu(),
+                        self.posterior_variance[1:].cpu(),
+                    )
                 )
             )
             .float()
diff --git a/src/synthcity/plugins/core/models/time_series_survival/ts_surv_dynamic_deephit.py b/src/synthcity/plugins/core/models/time_series_survival/ts_surv_dynamic_deephit.py
index 062902ac..a8363799 100644
--- a/src/synthcity/plugins/core/models/time_series_survival/ts_surv_dynamic_deephit.py
+++ b/src/synthcity/plugins/core/models/time_series_survival/ts_surv_dynamic_deephit.py
@@ -89,7 +89,7 @@ def _merge_data(
         self,
         static: Optional[np.ndarray],
         temporal: np.ndarray,
-        observation_times: np.ndarray,
+        observation_times: Union[List, np.ndarray],
     ) -> np.ndarray:
         if static is None:
             static = np.zeros((len(temporal), 0))
@@ -121,7 +121,6 @@ def fit(
     ) -> TimeSeriesSurvivalPlugin:
         static = np.asarray(static)
         temporal = np.asarray(temporal)
-        observation_times = np.asarray(observation_times)
         T = np.asarray(T)
         E = np.asarray(E)
 
@@ -146,7 +145,6 @@ def predict(
         "Predict risk"
         static = np.asarray(static)
         temporal = np.asarray(temporal)
-        observation_times = np.asarray(observation_times)
 
         data = self._merge_data(static, temporal, observation_times)
 
diff --git a/src/synthcity/plugins/core/models/ts_model.py b/src/synthcity/plugins/core/models/ts_model.py
index 34f6ac4c..e9fbde4f 100644
--- a/src/synthcity/plugins/core/models/ts_model.py
+++ b/src/synthcity/plugins/core/models/ts_model.py
@@ -493,7 +493,6 @@ def _prepare_input(
     ) -> Tuple:
         static_data = np.asarray(static_data)
         temporal_data = np.asarray(temporal_data)
-        observation_times = np.asarray(observation_times)
         if outcome is not None:
             outcome = np.asarray(outcome)
 
@@ -519,7 +518,7 @@ def _prepare_input(
             )
             temporal_data_t = self._check_tensor(local_temporal_data).float()
             local_observation_times = np.array(
-                observation_times[indices].tolist()
+                [observation_times[i] for i in indices]
             ).astype(float)
             observation_times_t = self._check_tensor(local_observation_times).float()
 
diff --git a/tests/plugins/core/models/test_mlp.py b/tests/plugins/core/models/test_mlp.py
index ac9a2db3..09b0c21a 100644
--- a/tests/plugins/core/models/test_mlp.py
+++ b/tests/plugins/core/models/test_mlp.py
@@ -71,9 +71,8 @@ def test_basic_network(
 @pytest.mark.parametrize("layer", [LinearLayer, ResidualLayer])
 def test_custom_layers(layer: torch.nn.Module) -> None:
     X, _ = load_digits(return_X_y=True)
-    Xt = torch.from_numpy(X)
-
-    mod = layer(Xt.shape[1], 10).cpu()
+    Xt = torch.from_numpy(X).cpu()
+    mod = layer(Xt.shape[1], 10, device="cpu")
     assert mod(Xt).shape[0] == Xt.shape[0]
     assert mod(Xt).shape[1] >= 10