It appears that on the last objective the players become invisible to the AI. Sorry guys, I didn't buy this game to take advantage of shit like that.
Everyone is gonna hate me for this.
@Legion_One
Yes ! I truly hate you now for this post !
No, i am just kidding buddy 
But you should choose a more meaningful sentence in the headline so that developers ( and other Forum members ) can see what the Topis is about !
The headline you chose is a so called " clickbait " and therefore people are going to hate you .... noooo, i am joking again
I had that phenomenon too ( only once ) a few days ago.
In a coop match on a custom server everybody except one guy died and we all were watching him, how he was trying to take the mission objective on his own.
There were really a lot of Bots protecting that spot but he could kill one after another without even getting shot once. The bots normally would have fired on visual contact, but they all just reacted like they had no ammo in their weapons. They run around and jumped from prone postion up and looked for cover or tried to flank him but not a single shot was fired on him.
So after killing each bot he took the mission objective and when we ( the rest of the team ) respawned the bots suddenly reacted as deadly as always, firing their weapons again on everyone of us.
This only happened once !
And to be honest i played dozens, may be 60 - 70 coop matches after the latest patch.
So that looked like a minor bug to me thats why i didn´t report it here in the forum, but now .... well... a few written lines might help developers.
Hey @Legion_One
Thanks for reporting this, I've passed it on to the dev team. 
And indeed, a clearer title would be appreciated.
