Are achievements disabled when playing with modded content?

I played a game recently where I should have gotten the Flawless Victory achievement, but I didn’t.

It was against a Cauldron villain so does that mean that all achievements are disabled for games with modded content? (Either that or I’m missing something stupid with that particular achievement).

Yes, achievements are disabled when playing with mod content, as mentioned on our website: Steam Workshop — Sentinels of the Multiverse: The Video Game

I must have missed that line, thanks.