I suddenly get an alert popup when creating a diff revision:
**Unhandled Exception ("InvalidArgumentException")**
Argument 1 passed to DifferentialChangesetHTMLRenderer::renderImageStage() must be an instance of PhabricatorFile, null given, called in /path/to/phabricator src/applications|differential/render/DifferentialChangesetOneUpRenderer.php on line 188 and defined.
and it won't be closed. what should I do then ?