Game slows down and crashes while trading with villager

Hello,

I've found a bug while trading with a villager,

When I was trying to get the woodland mansion map in creative from a cartographer villager, my game chashed. I did the normal order for a villager to unlock new trades, but when I came to the 3rd trade (some emerald for a map), my fps dropped and the game started to slow down rapidly. Then the screen when to a stop and so it crashed. I had this issue in the 18w22c snapshot too. 

This kind of crash where the fps drops in 10 seconds to a full stop, is what I had another time in the 18w22c snapshot, but in a differend way which I can't remember unfortunatelly,

I hope you can figure this crash out. If other people had the same kind of crash, please tell us.

Kind regards,

Digging_Dutchman