Insufficient mating material and still a win ??

Hello,
I was just surprised that I got a win awarded despite only having a knight.
While opponent has an A pawn and a Bishop and ran out of time.
I can see that with a lot of cooperation it is possible to mate if the opponent cooperates. But always thought that this cooperation rule only applied to having two knights and no pawn at the opponents side.

Is this a bug or works as intended?

Works as intended. Rules say its a win in that case. If you want the buggy version, you must go to the green pawn. :)

See another thread for details:

lichess.org/forum/general-chess-discussion/can-you-lose-on-time-if-your-opponent-only-has-a-minor-piece

(and there are few more).

Or just read the FAQ: lichess.org/faq#timeout