Gunner missing gun, crosshair problem in tanks, IFV etc....

Me and my friends are having problem with gunner seat on some maps, as some ppl reported before no crosshair, no ability to shot anything with machinegun on gunner seat. It's not on all maps and not always. yesterday i had this issue on flood zone, and my friend that was driving another IFV had simillar problem on same game. 

ps. it's on pc version.