Trading paper for emerald with a cartographer villager causes timeout on server, and all players get disconnected.

This now has happened several times in the 1.13 pre6 release. Every time you repeatedly trade paper for emeralds with a cartographer villager, the server will eventually give a time-out, and all players will be disconnected.  The server itself does not crash, and no stacktraces can be found in the server log.  It does say this though: 
[23:44:07] [Server thread/WARN]: Can't keep up! Is the server overloaded? Running 39074ms or 781 ticks behind.
That message only appears in the logs when this timeout happens.