fb2k seems to have trouble reading ID3v2.4 UTF-8 tags written with 2.43. When loading mp3s into a playlist and then right-clicking them, fb2k crashes in "ole32" specifically "OleSaveToStream".
I know this is a bug in fb2k, but it'll be useful to know if you've changed anything in the way ID3v2.4 UTF-8 tags are being written. The mp3s have one embedded image.
EDIT: Hm, the crash is gone now. I've reinstalled 2.42h and then 2.43 to test it on another set of MP3s. I've also rewritten the tags of the initial mp3s once as ID3v2.4 and APEv2 with both version again, last time with 2.43, then reloaded them in fb2k and right-click -> no crash.