Results: Fix non valid results save.

src/Model/Results/Results.py

@@ -349,10 +349,16 @@ class Results(SQLSubModel):
                     f"AND result = {pid}"
                 )
 
+    def _is_valid(self):
+        return "timestamps" in self._meta_data
+
     def _db_save(self, execute, data=None):
         if self._status.scenario.id != self._owner_scenario:
             return True
 
+        if not self._is_valid():
+            return False
+
         pid = self._pamhyr_id
         if self._solver is None:
             solver_name = self.get("solver_name")