I've noticed that songs coming up in the search results are occasionally greyed out, and I can't play them.This happens on mobile devices, the web player and the desktop player. I originally figured those were premium-only or something, but having started a trial I noticed they're still greyed out. I also noticed that the amount of greyed out songs seems to be increasing. At first I thought this was a regional block (I'm currently in Germany, and some of the greyed out music works in the Netherlands); in many cases, this applies to entire albums (such as this album). However, I'm increasingly seeing it on individual songs on an album (e.g., the first and eighth song on this album), and even on songs that I used to be able to play in the past.  Also of note- songs aren't greyed out consistently. For example, the album I linked above was added to a playlist by the band, and the songs look normal there.

related questions:

This question is similar, but the reason there was related to playing on a mobile device.

This question is basically the same as mine (I think...), but has gone unanswered for three years, so I figured I'd make a more detailed question about it.

This solved question supports the idea that a regional block is the cause, but I'm really confused as to how that relates to individual songs being blocked (as compared to full albums, which I understand). See also here and probably many similar questions.

Here it is stated that this also applies to unreleased material.

This suggests that album removals are also common.

Is there any way to see why I can't play these songs (unreleased/no artist permission/other reasons)?

Is there some kind of censorship setting in the client that I missed?

I did find a 'show unavailable tracks in playlists', which was turned off until I found it just now.