In Mission 3.3, a lootcrate can be found in one of the breakables.
Anyways, this lootcrate is not given after the match, it doesnt appear in the mission reward screen nor is it added to the total amount of lootcrates for your account.
Other players have this issue as well, as i found out in some YT video comments about the mission
Im not sure if this issue is only true for PC other other Platforms as well, but i added the prefix "PC" because i encountered it on PC:
I own the Gold edition of the Game from Steam.