Isn't this the same as MBS-2158 (and probably others)?

I notice that it actually not all recordings were forgotten, but it was certainly more than the single track that I actually edited.

No, it's not the same as MBS-2158. Here I had already associated the recordings in the editing UI, it was going back and forth that made them be forgotten. Perhaps it's the same underlying reason, though.

Any changes made on the recording tab should normally be remembered. So what you've described is definitely a bug.

I am not able to reproduce the problem however, can you add a little more details?

I assume you've used the 'basic' editor on the tracklist page. Please confirm this, and add which browser and OS you were using. (and re-open the ticket, I'm closing as cannot reproduce for now).

I'm unable to reproduce this now. Perhaps it was the tracks that I changed that got their associations cleared, and I was confused about what was happening. Will re-open if I see something unexpected again.

Yes, it was using the basic editor. Browser is Opera Next 10.50 alpha.