Personally I do not know why this happens, but I believe the reason is because SCE's and MCE's carry no data of a player who was supposed to have fired them. All projectiles have to carry some sort of data eg. the player who originally fired them. This is to prevent doing damage to self - like seekers from seeking and hurting the very player who shot them. Since MCE's and SCE's were not "fired" from a player, they do not seem to carry this data (or at least the data is wrong) which would explain why the game crashes only after someone gets roasted for the game does not know whom to increase the roast count.

Just my thoughts...