So far happened only once. Game declared victory and completed for a team of 2+ players (I think there were 3). I doubt it was "Prevent premature game completion" rule fault, my theory it was something to do with automatic team sizes balancing rule, perhaps during the time a player was being moved to another team - someone left or joined and something went wrong. Possible solution is right when a round is completed immediately call Disable Built-in gamemode completion then re-enable it once next round begins.
This was due to general cleanup not happening in very specific condition (score of one team increasing after a draw). Was causing several other issues. Fixed in 07e85d40d464c2f8f1d787e4387df13920084955.
So far happened only once. Game declared victory and completed for a team of 2+ players (I think there were 3). I doubt it was "Prevent premature game completion" rule fault, my theory it was something to do with automatic team sizes balancing rule, perhaps during the time a player was being moved to another team - someone left or joined and something went wrong. Possible solution is right when a round is completed immediately call
Disable Built-in gamemode completion
then re-enable it once next round begins.