I find this happens to me fairly often. It usually happens only for one map but no matter what map it is it lasts the whole battle, including Frontline battles! Which is very very irritating! I have reported this a few times with no reply from the devs? I don't know if they don't care or what but I wish they would fix it! I play arty alot! Especially in Frontline. So if devs are reading please fix it! It's an old problem and should have been addressed by now!