This bug can be reproduced consistently. Set up a few cartographer villagers, keep trading paper for emerald so they will unlock new levels of trade, and eventually this will happen:
[11:46:32] [Server thread/INFO]: Xena_Dragon lost connection: Disconnected [11:46:32] [Server thread/INFO]: Xena_Dragon left the game [11:46:32] [Server thread/INFO]: Dongersmooi lost connection: Disconnected [11:46:32] [Server thread/INFO]: Dongersmooi left the game [11:46:32] [Server thread/INFO]: Joene lost connection: Disconnected [11:46:32] [Server thread/INFO]: Joene left the game [11:46:32] [Server thread/INFO]: Nomicor lost connection: Disconnected [11:46:32] [Server thread/INFO]: Nomicor left the game [11:46:32] [Server thread/WARN]: Can't keep up! Is the server overloaded? Running 35350ms or 707 ticks behind
This bug can be reproduced consistently. Set up a few cartographer villagers, keep trading paper for emerald so they will unlock new levels of trade, and eventually this will happen:
[11:46:32] [Server thread/INFO]: Xena_Dragon lost connection: Disconnected
[11:46:32] [Server thread/INFO]: Xena_Dragon left the game
[11:46:32] [Server thread/INFO]: Dongersmooi lost connection: Disconnected
[11:46:32] [Server thread/INFO]: Dongersmooi left the game
[11:46:32] [Server thread/INFO]: Joene lost connection: Disconnected
[11:46:32] [Server thread/INFO]: Joene left the game
[11:46:32] [Server thread/INFO]: Nomicor lost connection: Disconnected
[11:46:32] [Server thread/INFO]: Nomicor left the game
[11:46:32] [Server thread/WARN]: Can't keep up! Is the server overloaded? Running 35350ms or 707 ticks behind