I'm almost certain that is true, but I don't think the two issues are related, because even when the states are definite, ie, I am playing music and I tell it to stop, with or without an evaluation, I get this error.
But yes, I'm not sure how useful the ISMUSICPLAYING() evaluation really is, because certainly in my testing using debug prints, it quite often reports that it's not when it quite obviously is (to clarify, playing a non looped track, 'ISMUSICPLAYING' reports true in a looped evaluation for some of the track, then seems to stop early. I mean, very early. Like, seconds away from the end). I have no idea how it's evaluated, but I had idly wondered whether it had anything to do with bitrate of the mp3, ie, yes, it plays, but isn't '100% compatible'. Or I could be way off base

But really, thats not the issue so much here. I simply want to issue STOPMUSIC when paused, or when ending the game. And that always generate this buffer error.
Though yes, solving the pausing/stuttering in what ought to be a seamlessly looped track would be nice to solve, too!
I had considered, given that I know the exact length of my track to the millisecond, creating a timer function that forcibly replays it NON looping, but haven't gotten around to testing the theory yet to see if it's any more agreeable than the noticeable pause it causes when set to loop. It might well be a futile exercise, given that the one command to loop, with no evaluations, ought to have far less overhead than an extra timer, constant evaluation and reissuing the play command, no?!