King of the mists unable to collect tribute reward

I was unable to collect a tribute reward after killing king of the mists while playing couch coop with another person. We were both using controllers and unable to select any tribute reward. We did receive the Gembloom Skull item for a permanent buff. Oddly, we were also unable to use the town portal. We saw a message saying that it was unavailable during boss fights.

exactly the same bug here. Can't move the tribute reward to inventory. Playing in couch co-op mode.

Update: The bug can be bypassed by leaving couch co-op mode and clearing the area in single-player.