Cannot edit any metadata for purchased song (including adding lyrics)

I've always been able to modify everything, say if the album or the genre weren't "correct", and most importantly, I've always been able to click the "add custom lyrics" and either copy paste or just straight up type in the box, but the other day I purchased a song from the itunes store and not only I wanted to change the album from "[song- single]" to the title of the actual album, but most importantly I wanted to add the lyrics, yet even though I am allowed to click the box, I cannot type anything in it. I thought maybe there was a mistake in the website where I found the lyrics but even trying to type random stuff in, no character appears. It has never done that, either for songs I purchased digitally or for ones I copied from physical cds, did this happen to anyone else? Any solution? Thanks