If you get the mission while your quest menu is full and the postmaster is full the quest cant be acquired through the altar by Eris under abandoned quests and when you try and grab the quest it says can only hold one of these. I tried to do the quest steps for essence of pride with it missing from my inventory and nothing happened. I tried restarting destiny and the glitch is still there. So now I can't complete most of the activities for all of shadowkeep. I've seen that multiple people are having the same problem as me so it must just be a bug.