Hello!
The same problem! I play with ARMA 2 CO ... With or without addons still have this problem!
For my part, from the beginning of the mission while normally happens! It was after my first death (respawn or revive) I become invisible! I can not even get on a helicopter or other vehicle! (No rank)
I am therefore obliged to disconnect me from the server and reconnect me to be able to play again normally until my first death ... And so on ...
Have you got a solution to this bug Please!?