From getting into more and more firefights I have notice that there are apparently a lot of invisible walls.
I tried shooting a person through a gap between 2 rocks (placed 1-2 meters from each other) and I didn't seem to hit the person on the other side of the gap. But from the other side of these rocks you can shoot through them. So I died.
This seems to be also true for about all the fir trees. This is especially a big deal as players like to hide underneath these trees. You can stand 2 meters from a person in a fir tree and shoot his body head to toe and miss everything because the bullets are bouncing off of an invisible wall.
Lastly from my experience, this seem to occur when shooting up and down a hill. Where when you shoot at a person that's prawn on a hill it seems the ground or the grass can become an invisible wall when shooting the person from the same height on that hill. This situation has happened to me less then the fir trees and the rocks.
However I have experienced the hill bug more often in combination with a fir tree placed up a slope/hill, but my guess is that the tree was at fault for that invisible wall making my bullets bounce of and getting killed in the progress. It also seems that an invisible can exist from one side but from the other side the bullets go directly where there aimed at.
So in short there seem to be invisible walls near rocks and near fir trees or even created by these objects and these are probably not the only objects or structures in the DayZ environment that has this problem.
I haven't created any video evidence yet, but my guess is that this is a common bug well-known to the developers. I'd just like to emphasize it.
But if it's not well-known then there is this post and I would of course happily provide some video of this phenomenon.