I had a similar experience recently. I have my “liked list” that I play in my car while driving. Idk like 300 songs. My car is old as shit so I have to have a dongle attached to an aux cord plugged into my phone and a tiny aux Jack in the bottom of my center console. Well, sometimes I’m in the mood for songs and sometimes I’m not, so I’ll poke my screen to skip a song or two while driving. One day I was searching for a particular song and it wasn’t found in my liked list.

I finally figured out why it didn’t show up. There’s a bunch of clickable buttons right below the play button “hip hop, pump up, aggressive “ etc. Long story short, I had accidentally clicked one of these buttons and it had hidden half my liked songs. So I had to un-click that, and then all my songs were back again.