The helicopter has several bugs. First, it causes lags as soon as it appears on the server, and everyone is affected. The pings can go up to 1020. Then I hit it a second time after a teammate touched him a first time at the RPG. He then fell slowly like a feather! Finally when it crashes, it remains whole and can even pass through the walls.
Also, climbing a staircase I literally went down the stairs and I had to kill myself with my RPG ..