BugFix: Clean cached field, if no data is available

models.py

@@ -424,14 +424,16 @@ class Item(models.Model):
         for key in self.MODEL_TO_MEDIA_DATA:
             value = data.get(key)
             if key == media.metadata.KEY_GPS:   # Split GPS data in lon and lat
-                if value is not None:
-                    for k in self.MODEL_TO_MEDIA_DATA[key]:
-                        setattr(self, self.MODEL_TO_MEDIA_DATA[key][k], value[k])
+                for k in self.MODEL_TO_MEDIA_DATA[key]:
+                    value_k = value[k] if value is not None else None
+                    setattr(self, self.MODEL_TO_MEDIA_DATA[key][k], value_k)
             else:
-                if key == media.metadata.KEY_TIME:  # convert time to datetime
-                    if data.get(media.metadata.KEY_TIME_IS_SUBSTITUTION) and self.type == TYPE_IMAGE:   # don't use time substitution for images
-                        break
-                    value = datetime.datetime.fromtimestamp(value, tz=datetime.timezone.utc)
+                if value is not None:
+                    if key == media.metadata.KEY_TIME:  # convert time to datetime
+                        if data.get(media.metadata.KEY_TIME_IS_SUBSTITUTION) and self.type == TYPE_IMAGE:   # don't use time substitution for images
+                            value = None
+                        else:
+                            value = datetime.datetime.fromtimestamp(value, tz=datetime.timezone.utc)
                 setattr(self, self.MODEL_TO_MEDIA_DATA[key], value)
 
     def __update_other_file_data__(self, full_path):