I just stumbled across the fact that a 5e character sheet defaults (e.g. Encumbrance on or off) can be changed. I updated those settings but it appears to have somehow purged my existing player pool in the game. Those character sheets that were assigned lost the player details and until they log back into the game, they don't even appear as a viable option for assignment. Not a major issue, but I thought I should raise a flag about it.