With the VisualEditor "New wikitext mode" feature on in Beta settings, if I try to move an article or user page and it fails, the wikitext editor suddenly loads to edit the page I was trying to move, although the URL shows that it is trying to edit Special:MovePage itself...?
To reproduce:
1. Make sure the "New wikitext mode" feature is on in Beta settings
2. Go to any article or user page that would normally be editable by VisualEditor
3. Use the Move page, and cause an error by trying to move the article/userpage to where it already is
4. When you get the error page, the VE wikitext editor will load, giving you the wikitext contents of the page you were trying to move. However, the URL will change to https://en.wikipedia.org/w/index.php?title=Special:MovePage&veaction=editsource.
Note that this happens on any error from MovePage - it doesn't have to be the "trying to move an article to itself" error, I discovered this bug when I tried to move an article to a location that was locked from creation by an administrator.