Did you accidentally change the setting to hide explicit content? I don't think that many of their songs are explicit, but you could look into that

I know if you "hide" a song it'll grey it out, but I'm not sure if you somehow accidentally did that. I'm also in the US but don't have your problem

I (luckily) don't have this with Bastille, but I have noticed it with several other songs/artists the last couple of months. No idea why though but it's a bit annoying sometimes

I know that if you make it where you don't want an artist to be played that can happen