Ok, this is a bit technical, but the way the game works seems to be as follows:
--Player1 plays a singleplayer world, and opens it to LAN
--Player2 joins and collects some stuff
--Both players quit
--Player2 loads up the single player world, and the "singleplayer inventory," stored in the level.dat file, is loaded and OVERWRITES Player2's inventory from the last session.
--Player1 joins and keeps their same inventory
--So basically, Player1's inventory has been duplicated and Player2's inventory has been deleted.
It's true, few players will run into this situation, but it has been a thorn in my side with all the tinkering I do, and would still be worth looking into! At least have a menu pop up that says something like, "Load Player2 LAN Inventory or keep Singleplayer Inventory?" Of course, if it's a player who hasn't been on the map before it could skip the menu.
Thank you for your report!
We're actually already tracking this issue in MC-697, so I resolved and linked this ticket as a duplicate.
If you would like to add a vote and any extra information to the main ticket it would be appreciated.
If you haven't already, you might like to make use of the search feature in the future to see if the issue has already been reported.
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