This is annoying, but it's part of the game tactics, though it would be nice if someone added different checkmate rules to pick from
Flaw in 4PC

Please post things like this in the game rules forum instead of creating a separate forum, so can one of the admins lock or delete this?

Please post things like this in the game rules forum instead of creating a separate forum, so can one of the admins lock or delete this?
Bruh how would this go in the gamerule forum lol

But yeah on the point of this forum, the trick is not to finish 'weaving' a mating net until you have a direct mating threat and have defended the position from other colors trying to steal the 20 points.
However, this is part of the 4pc tactics like CzarnyResorak said
There is a major loophole in the checkmate system of 4 player chess, if the pieces of different colours combine checkmate another player, the points automatically go to the one who delivered the final blow. If one player spent half their game weaving a checkmate net and another player swoops in and steals the kill, it would be unfair for the player who weaved the mating net. At this point, the first player who was preparing checkmate may even want to sabotage the checkmate on the king in order to steal back the kill from the sudden attacker. My suggestion is to make it a capturing the king variant but the king cannot move into check, because the concept of checkmate here seems unfair. I believe that this has already been implemented, but checkmate also counts, so I believe that it would be best if we removed it. If it is the checkmated player's turn, then the points go to the last player to check them. This can be achieved by simply waiting till the checkmated player's turn before awarding the points for checkmate