Treasures of Utzaal Hammer and Oswald

My friend and I were playing couch mode and got to the Molten Vault boss fight to complete the Treasures of Utzaal mission. We completed the boss fight and got the hammer but when we got back to the encampment, Oswald didn't spawn, even though the mission was saying he should've been in the encampment. After about an hour of trying different things to get him to spawn in home base, I went onto single player on my Monk and all of a sudden, Oswald spawned in. So I completed my quest but when we swapped to his Archer, Oswald still wasn't spawning. I would like to hear any ideas that anyone might have.

I have the exact same issue with couch play. Coming back in with 1 player solo, I was able to complete. When we come in solo with other she still has hammer but Oswald is not in camp. Tried dropping hammer and picking back up quest, but still Oswald isn't in camp to complete.

Having the same issue in couch coop.