I've been playing arma again for a while and I noticed that opponents can't see me, but I can see them. When I then switched to a map other than Altis I found this (see screenshots). Roughly, no (or only very faint) leaves on trees or bushes are displayed to me, as well as grass.
I have no idea what the problem could be.
Screenshots of my Settings: (I have reset everything to default, so it shouldn't be that.)