diff --git a/src/cellrank/estimators/terminal_states/_gpcca.py b/src/cellrank/estimators/terminal_states/_gpcca.py
index edf78cfd..cc55dd26 100644
--- a/src/cellrank/estimators/terminal_states/_gpcca.py
+++ b/src/cellrank/estimators/terminal_states/_gpcca.py
@@ -1051,7 +1051,7 @@ def plot_macrostate_composition(
         mask = ~macrostates.isnull()
         df = (
             pd.DataFrame({"macrostates": macrostates, key: self.adata.obs[key]})[mask]
-            .groupby([key, "macrostates"], observed=True)
+            .groupby([key, "macrostates"], observed=False)
             .size()
         )
         try:
diff --git a/src/cellrank/kernels/utils/_tmat_flow.py b/src/cellrank/kernels/utils/_tmat_flow.py
index c2fbd75d..d12c9fd1 100644
--- a/src/cellrank/kernels/utils/_tmat_flow.py
+++ b/src/cellrank/kernels/utils/_tmat_flow.py
@@ -180,7 +180,7 @@ def cluster_helper(t1: Numeric_t, t2: Numeric_t) -> pd.DataFrame:
             subset, row_cls, col_cls = self._get_time_subset(t1, t2, cluster=cluster)
 
             df = pd.DataFrame(subset.toarray() if sp.issparse(subset) else subset).sum(0)
-            df = df.groupby(col_cls, observed=True).sum()
+            df = df.groupby(col_cls, observed=False).sum()
             df = pd.DataFrame([df], index=[cluster], columns=df.index)
 
             res = pd.DataFrame(np.zeros((1, n)), index=[cluster], columns=categories)