Exporting MP3 and WAV mutes some, but not all instruments

[Jurmicc]

Up until now, I've never had an issue with exporting sequences as WAV and MP3, but yesterday I tried exporting my remix of Raise Up Your Bat () as an MP3 and a WAV and many of the instruments are completely muted in the audio file, but play just fine here on the site. Most obviously, when exported in either format, all you can hear at the start are the Ride Cymbal 1s from the 2023 Drum Kit.
I tried exporting again this morning. Didn't work.
I tried clearing my browser cache and then exporting. Didn't work.
I tried exporting from MS Edge (which i never use) instead of my usual Chrome. Same result.

[spira.]

I have this problem too. No matter what I do, when I download as an mp3, it gets rid of all the reverb.

[minigogo]

Same for me, except it's a single instrument (distorted guitar). Have tried changing the instrument on that track, removing 1/8th notes, and removing a note-heavy section, but no dice.

[Jurmicc]

Just exported the same Raise Up Your Bat sequence again a moment ago as both a WAV and an MP3 and everything seems to be exporting correctly again for both file types!

[GamemakerX1]

I usually export using midi. However, the synth goes "CRAZY" every time I do it. This is kind of why I don't use synth that often. I think synth is incompatible.