Both A Timely Matter and Mr. Markov I Presume are m4a files, but I'm getting reports it doesn't play on certain devices (seemingly Apple specifically) whereas I can play them well enough.

I did have an issue with Mr. Markov I Presume where on Win 10 Chrome it didn't play to the end; I switched to my mobile and was able to hear the whole thing. Didn't think to mention it because I thought it was a problem on my end.

I take it you also have problems with bc likes you songs?

Yes. None of those play.
I wouldn't mind if they didn't make the playlist get stuck at them, or if we could actually add users to a "ignore list" so we never "hear" their songs (not like I can hear anything from those two users, as I said, their tunes don't work, ever)

There are problems in Chrome too, remember I keep bitching about this in the forums.
Parallelis: interesting, maybe SOME m4a settings make this a problem. Your tunes do play in my browser, unlike mnapoleon's tunes
https://weeklybeats.com/mnapoleon
not . a . single . tune . plays

Yes, clearly there's something wrong with the M4A format, or the M4A support in the player at least, because another song of mine also in M4A doesn't play at all using a different exporter. I take it you also have problems with bc likes you songs?

There're also songs I can't play in my browser that are m4a, mostly all of these and all of these (though they work fine if I download them, so it's maybe a browser thing).

This has never happened before with mp3, so something screwy is going on here.