Fix for manual cache creation

__init__.py

             self._cached_props[self.UID_TAG] = self._source_instance.uid()
             self._cached_props[self.DATA_VERSION_TAG] = self._source_instance.data_version()
             self._cached_props[self.STORAGE_VERSION_TAG] = self.STORAGE_VERSION
-            self._save_cache()
+            if self._store_on_get:
+                self._save_cache()
 
     def _load_cache(self):
         if os.path.exists(self._cache_filename):