Thats how it works in the build im playing right now. Which is the latest dev-build. You take no damage if you take cover behind a wall, road/h-barriers, building walls etc. I found a few spots that didnt work however. Would be great if youd be more specific if you have the issue with some situations that you think should be changed.

pretty easy, i have heard USMC in iraq or afghan that got fucked up because they threw a grenade inside one of those mud-dirt houses and the house itself blew up, however, in greece you se concrete walls and houses, wich could stand a grenade explosion.

check also the Flashbang addon for the game, in the video of the addon you see the flashbang breaks the windows of the house it was thrown into, and the windows of the surrounding houses, even though a flashbang has no effect after a wall.

Not sure, but i think a vehicle DOES provide explosions cover

I undesrstand, but what im saying is that the walls in ARMA3 protect you from grenade explosions already. I tested it myself.

Unless you found where it doesnt work.

well, it doesn't for me

Try out the dev build. Maybe its that.

renamed title and description to fit whats going on