Maven invitations

Hi! can someone explain me why my friend didn't get completion for any maven invitations after killing them in my map? we did formed,hidden, twisted and elderslayers , but none of them gave him any atlas skill point. I initially thought it's related to come uncompleted quests , but he got all of them regarding the atlas, he did the 10 bosses maven invitation 2 times and that is pretty much all the info I got...

You can have Maven witness all the required boss encounters with a party and everyone present will get credit. But completing an actual invitation gets credited to the instance owner only. You need your friend to open them so he'll get credit.