Shuffled playlist won't play songs recently added to the playlist

[acikprt]

Plan

Premium

Country

USA

Device

Samsung Galaxy S7 Edge, Desktops

Operating System

Desktop (Windows 7, 10)

My Question or Issue

Yesterday, I added about 60 new songs to a long playlist with about 450 songs already. Those new songs don't appear at all in the queue when I set the playlist to shuffle. This occurs both on my two desktops and on my phone (which is strange, since my phone usually puts recently-added songs early on in the shuffle queue). I've tried restarting the app, on all three devices, and logging out of the app. I've tried removing the added songs and putting them back in one or two at a time. I can play the songs by selecting them manually, and they'll play if I don't put the playlist on shuffle. But if I shuffle, they don't show up at all in the upcoming queue, even if I scroll past a hundred songs.

(I put this in the Your Library forum, since this doesn't appear to be device-specific.)

((Also, while I'm here, what's the best forum for mentioning errors in track titles?))