I tested this with a friend of mine who has much better specs than I do, and thus he's able to load into the game much faster than me.

When he hosts a match, he will load in quickly as is usual. I will take a few extra seconds to load in. During that extra load-in time, the game/mod will not track anything for the entire match. I won't get exp, and the game mode will get stuck on screen until we end the match.

However, if I host the match, these issues don't occur. It will load up the stats and I can level up and all camos I unlock will still track