[2022] Leaver penalty, but never left?

Is this a thing that happens sometimes?

It was a ranked game so a bit of a bummer. I got a leaver penalty, I never left, afk'd, d/c, or sat around doing nothing or anything like that at any point during the game. In fact I was even doing quite well in the game with a positive kda and high teamfight contribution etc.

I got a message about being idle and needing to do something in the middle of an actual teamfight! I thought that's weird but surely it was a buggy message..

But nope, a few minutes later when chasing after scuttle or something I get the message that I'll be punished and I was.
Has this happened to anyone else before? It really bummed me out.