Playlist as alarm tone problem

Detailed description of the problem:
I can select new m3u playlists stored on my phone, but they won’t work (still playing a beeping sound). When I click on the playlist button (top right most) I can see only old playlists, even with duplicates, but not any new ones. When I select the folder button (top second from right) I can select the new m3u file, but it doesn’t play (it does play fine in my media players - I use Poweramp). Interestingly, some of the old playlists work and it says “playlist of size xx”, while for the non-working it just repeats the m3u file name.

It almost looks like the problem in this thread, but I don’t see any x’s to remove old/non-working playlists.

Steps to reproduce:
Go to Settings > Alarm default settings > Ringtone, select the top right most playlist icon and it shows the old and duplicated playlists. I can select them and some work, others (duplicates) won’t. Select the folder icon on the right (in the search box) and I can select a new m3u playlist, but it won’t work. I can also select a non-working playlist and pressing the trash icon in the green banner on the top, but it doesn’t delete the playlist.

Version of Sleep as Android:
20190925 (latest from Google PlayStore)