Save the OpenMM state after a GCMC move.

Author: lohedges

src/somd2/runner/_repex.py

@@ -1265,9 +1265,6 @@ def _run_block(
                 ),
             )
 
-            # Set the state.
-            self._dynamics_cache.save_openmm_state(index)
-
             # Perform a GCMC move and write ghost water residue indices after
             # dynamics so that the ghost state is temporally consistent with
             # the saved frame.
@@ -1289,6 +1286,9 @@ def _run_block(
                 # Save the GCMC state.
                 self._dynamics_cache.save_gcmc_state(index)
 
+            # Save the OpenMM state after any GCMC move so the context is consistent.
+            self._dynamics_cache.save_openmm_state(index)
+
             # Get the energy at each lambda value.
             energies = dynamics._current_energy_array()