Holding a loaded map causes internal server error in multiplayer game. For sure here is a link to video: https://www.youtube.com/watch?v=dI5MpIyCsak&feature=youtu.be
It appers only in this version, on 20w11a everything worked fine.
Unloaded map doesn't causes any problem nor empty map.
Thank you for your report!
We're actually already tracking this issue in MC-175218, so I resolved and linked this ticket as a duplicate.
However, that ticket has already been resolved as Fixed. The fix will arrive in the next version or is already included in the latest development version of the game.
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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