How to reproduce:
http://beta.musicbrainz.org/release/add
Use any Title like "Some Title".
Set Artist to "Various Artists" (compilation)
Click "next"
Add >= 1 tracks
Click "next" without adding any titles or artists

What is supposed to happen:
Warnings and tracklist displayed
here it would be:

A track name is required on track 1
A tracklist is required

What happens:
The warnings are displayed,
but instead of the tracklist only

is displayed forever. (well at least a couple of minutes)

This seems to be triggered when the tracklist is empty, which doesn't happen on non-VA releases, since they always have the artist pre-filled.
This is triggered with MBS-6928, but not only in that case.
Note that in "how to reproduce" I didn't do anything with a TOC here.