After the 1.38 update sometimes a camera shake effect occurs - every 3 seconds or so - that doesn't stop. It's similar to the newly added effect when cornering with a vehicle at higher speed but not as severe as a helicopter fly-over. It makes aiming difficult which is (hopefully) not intended.
I'm not sure what caused this, but three people, including me, noticed it after driving in an armed offroad for a longer time and then proceeding on foot. So far I've only encountered in in MP.