When you quit the game in the demo and you open the game again your UUID resets, causing statistics, advancements, village popularity and several other things to reset.
Linked issues
is duplicated by 1
Comments 8
Some behaviors that occur because of this glitch
Foxes no longer trust the player that bred them
Endermen and bees are no longer angry at the player that angered them. (This may be intentional as the server in a single-player world restarts when the player saves and quits to the title screen).
Tamed dogs and cats that are sitting stay sitting, even when the player that tamed them right-clicks on them.
Villagers also no longer give discounts to players that unlocked their master-level trades or cured them.
The skin for the player changes randomly from Alex to Steve and back.
If one looks in the "playerdata" folder in the demo version of the game, there will be multiple pairs of .dat and .dat_old files for different UUIDs, showing that the changing UUIDs are the root cause of the problem.
Relates to MC-196230
Clone of MC-190552