"[WARNING] Failed to load player data for Courtes"
This happens every time the server crashes or power goes out. When the system comes back up, the player.dat of logged in players is always empty.
Inventory is wiped and spawn reset. I have to avoid using ender chests, because I understand it would wipe that, too.
There must be some way you could avoid it--world chunk data never seems to be lost.
There is nothing the server can do about saving data after a crash or force shutdown. Shut down the server properly (
/stop) to prevent these problems.