Thats a pretty usual bug caused by the spectator-cam
That is not a bug. SCAR-H has high recoil so it is suppose to go up into the air without recoil management. At 2:21, he gets a kill while shooting way above the target you cannot see through his red dot scope. Then at 2:49, you see him aim down sight repeatedly his soldier says "spotted a sniper" then at 2:50, he tries to shoot at the spotted sniper (who is probably in one of the buildings) but cannot hit him. You just see him spraying up into the sky without any hit markers appearing. It appears in this video, he may be using some kind of wallhack, but the video is too short to confirm it.