keep getting very annoying client error

i keep getting some sort of client error which sends me back to lobby, i've had it loads of times 2 times in alaska when i was just walking to pick up weapons and twice in port mm today for no reason, so actually i completed my missions 3 times! why does this keep happening? it's outta control! isn't it just to stop glitching, not when your just playing the game? it's very frustrating and i would like it dealt with immediatly.