Click on edit on a page that doesn't exist

An api request is made to:
/w/api.php?format=json&action=query&prop=revisions&rvprop=content%7Ctimestamp&titles=Jdlrobson%2Fvector.css&rvsection=1

Which returns
{"query":{"pages":{"-1":{"ns":2,"title":"User:Jdlrobson/vector.css","missing":""}}}}

and an exception is thrown

The ajax loader continues infinitely.

Version: unspecified
Severity: normal