Some of the rocks on the north eastern shore of Altis at this particular beach have bad collision detection. You can for example walk inside one of the big rocks, and another one you cant walk on or throw grenades over or even shoot over, even if you CLEARLY arent hitting the rock but instead shooting/throwing over the rock, the "hitbox" seems to be way too high for that particular rock/ it has a invisible wall.
This is really hard to explain on a piece of text, a video would be much more informative however I am not able to record any gameplay at the moment.
The grid for the rocks is approximately 248237, ive only tried out the rocks on the more northern part of the rock formation.
I know rocks have never really been the strong part of arma and they arent the most important thing to focus on right now, but since Altis is full of rocks these things should be looked into, and to fine tune the collision detection or whatever it takes.
Im not looking to have arma become a cliff climbing simulator ;), but rather get the map and objects playable, refined and balanced all around.