I started the Shadowkeep campaign while my bounty list was full. After completing the first mission and visiting Eris at the Encampment, the next two quests went to the postmaster, including the one I described the title. I’ve retrieved the quests but can longer complete this one for some reason. I’ve revisited Eris per the quest instructions, but nothing happens. A google search revealed many others having the same issue. It may not be widespread because it seems to only happen if your quest log is full when starting the Shadowkeep campaign.