Additional video

https://www.youtube.com/watch?v=b6bWaeSN9iM&feature=youtu.be

Just submitted a video on this aswell, it's a pretty big problem when it comes to PVP in arma 3. Many headshots that haven't killed people most likely due to this. Also the fact that people can sink below walls far enough that players can't see them when they are shooting over it is a huge issue. Looks to people that the wall is shooting them.

The people logging this issue are aware of the Arma feature that sinks players into the ground to simulate grass (T64165) but the request is to have an option to disable this (especially for multiplayer) where hitbox detection and LOS issues cause unexpected behavior in the game.

The videos above are good examples where the engine masks expected outcomes by visually tricking the user.