There are a few cases like this: when an opponent lost, the opponent doesn’t resign, and doesn’t accept the scoring. If you click their profiles sometimes they are playing another new game.
Is it possible to deal with these cases? It can be confusing and i used to wait for 2 minutes until realising that the opponet just left the game without a word.
I guess try contacting them first, but there is a timer in the scoring phase, if your opponent does not accept/change the result before this timer runs out it should auto accept the current result.
If you are sure of some intentional mischief you can call a moderator from the right slide-out panel who will then solve the issue (might not be immediate, so be patient or play another game in the meantime.)