One of the many ways I use MP3tag is when I'm digitizing vinyl. I rip the music, then open it in MP3tag and import metadata using the appropriate Discogs Release ID. It's been working great until recently.
In the last month or so, the tag to track mapping is getting screwed up somehow. Not always, but once in a while. I don't notice it right away, and many still work well, so I haven't yet got any repeatable examples.
Since I haven't tracked this down totally yet I haven't filed a bug report, but I thought I'd see if anyone else is having an issue. I suspect non-standard track numbering on Discogs, but so far I have no confirmation, and the one I saw might be a coincidence.
I'm on Windows, and update to the latest production version religiously when notified.