I can't reproduce this - I get back to VisualEditor (as expected) - the login link is something like https://en.wikipedia.org/w/index.php?title=Special:UserLogin&returnto=Foobar&returntoquery=veaction%3Dedit

Can "Professor Hog" give any further details? What browser were they using? Can they reproduce? What about after a hard-refresh? Do they have any odd gadgets on the account into which they were logging-in?

I'll ask for further clarification, but I've tested this in Firefox 23 on linux.

Clicking the link in the VE popup that notes you're not logged in reproduces this bug. (Note that this loads the login window in a new tab, I logged in there and was returned to the source editor in that window).

Dismissing that popup and then using the log in link at the top right of the page returned me to viewing the page not editing it in either editor.

The results are the same using my Thryduulf account which has a couple of gadgets, and my Awkward42 account which has none.

To clarify the sequence I used to reproduce this was:

1. log out
2. load a page in VE. I tested with [[Symphony No. 8 (Mahler)]] and [[user:Thryduulf/sandbox]]
3. click to edit the page in VE
4. Click the "log in" link in the notice that pops up.

This loads https://en.wikipedia.org/w/index.php?title=Special:UserLogin&returnto=User:Thryduulf/sandbox&returntoquery=action%3Dedit in a new tab.

5. In that new tab, log in as normal

Get returned to the source editor.

The edit notice shown is that in [[MediaWiki:Anoneditwarning]] where the link is hardcoded to the source editor (pre VE this would never have been an issue).

To me this suggests that either editor-relative urls are needed or we need different edit notices for the classic editor and VE (see bug 52741 for the latter)

(In reply to comment #3)

To clarify the sequence I used to reproduce this was:

1. log out
2. load a page in VE. I tested with [[Symphony No. 8 (Mahler)]] and

[[user:Thryduulf/sandbox]]

3. click to edit the page in VE
4. Click the "log in" link in the notice that pops up.

This loads
https://en.wikipedia.org/w/index.php?title=Special:UserLogin&returnto=User:
Thryduulf/sandbox&returntoquery=action%3Dedit
in a new tab.

5. In that new tab, log in as normal

Get returned to the source editor.

The edit notice shown is that in [[MediaWiki:Anoneditwarning]] where the link
is hardcoded to the source editor (pre VE this would never have been an
issue).

To me this suggests that either editor-relative urls are needed or we need
different edit notices for the classic editor and VE (see bug 52741 for the
latter)

Oh, I see, I was clicking on "login" in the personal links bar - sorry. Re-titling so I don't get confused again. :-)

Changing the depends on to bug 52471 (sorry, I typoed in comment 3)

Note, Steven added a custom workaround at English Wikipedia (shortly after this was filed). It removes the action=edit, so you don't go to any editor on return (otherwise, it can to the wrong one like this bug says).

That was never the desired behavior, though. The desired behavior is that it knows which editor you're using anonymously, and keeps you on the right editor when you return logged in. Both VE and wikitext have suitable URL parameters; the issue is knowing which to use.