Steps to reproduce:
Click the tracklist tab
Click the edit note tab
Expected outcome: Track times are not touched
Result: It wants to remove the track times
Confirmed that it doesn't happen on the main server.
Three more where it happens:
It seems to happen when the medium has a disc ID. All the ones I've checked so far where it's happened have had disc IDs, so I tried editing a random release with a disc ID and it happened there too.
A Git bisection points the finger at commit 6521f0457a836866058b.
(committed to mbs-4382 branch, will be shipped to beta once the other issues opened for that branch have been resolved)