Implement fix

Author: baskrahmer

src/lightning/pytorch/callbacks/model_checkpoint.py

@@ -338,6 +338,13 @@ def on_validation_end(self, trainer: "pl.Trainer", pl_module: "pl.LightningModul
                 self._save_topk_checkpoint(trainer, monitor_candidates)
             self._save_last_checkpoint(trainer, monitor_candidates)
 
+    @override
+    def on_train_end(self, trainer: "pl.Trainer", pl_module: "pl.LightningModule") -> None:
+        """Ensure save_last=True is applied when training ends."""
+        if self.save_last and not self._last_checkpoint_saved:
+            monitor_candidates = self._monitor_candidates(trainer)
+            self._save_last_checkpoint(trainer, monitor_candidates)
+
     @override
     def state_dict(self) -> dict[str, Any]:
         return {