What kind of bug was this?

Take a look at this game of mine: lichess.org/3zaNq2vp
Everything was fine until the last move. So, I moved my rook to d8 and just premoved pawn capture to d8. Then I thought: "Let's not mess things up with premove" and clicked on the board, so the premove is canceled(I do this a lot of times) Everything seemed fine, I thought opponent left since he lost the game and I was waiting for his time to run out. And then I was waiting and waiting, seeing my last move on the board and opponent clock ticking. And then just I saw I LOST on time. I didn't lost connection or something like that, seems like a weird behaving. Can I get points refunded or it's my fault?

Was his time ticking in the end, or was it yours? If his time was ticking and you lost on time, then it sounds like a network problem. Are you using an old web browser?

I am 99% sure that it was his time ticking. Weird thing is that when I saw that he doesn't move piece for like 20 seconds I opened another tab on my 2nd monitor and opened sports website to browse sports news since I was expecting his time to run out and I didn't saw any network problems. Maybe it was problem only with lichess. :/

I had a bug like this once too

I forgot to answer the question: I use Google Chrome Version 97.0.4692.71 (Official Build) (64-bit) , so its not old browser.

You have lag.
lichess.org/lag