Hey, I just stumbled across a fix for this. It's certainly not ideal, and they need to fix it, but it might do for some people for now.
I originally loved about 12 songs when viewing a particular album. After that, I was looking at the songs in the My Music area and I could not unlove them. I could love and unlove other songs on that page, but I couldn't unlove those 12.
To get them unloved, I went BACK to the album view and unloved them all there. Then, I went back to the My Music area and unloved them again, and they were successfully unloved.
To be clear, the album page I'm referring to is the one you see when you're playing a song and click the ... then click "Go to Album".