Coke maan

So I can't get any achievements in coop. They are host only. If I join my friend, only he gets the achievements. I've tried the following achievements in his game: Fine Dining, Lounging Around, Beefing Up, Exoskeleton, Face your Fears. None of them worked. Not sure if the problem is on my side, but I even tried multiple accounts, nothing worked for me. Hope this can get fixed!