Crashing when joining LAN - two accounts on the same computer

When joining LAN world game crashes (two different accounts on the same computer). No issues with earlier versions.

Crash message:
"The game crashed whilst tesselating block in world Error: java.lang.NullPointerException: Tesselating block in world"

Crash report unclickable.

Link to unlisted video (on YouTube) showing the chain of events:
https://youtu.be/E6EBSH2l4BE

Why would you have two accounts open at the same time, you might be wondering? It's the classic "camera account"-trick, to be able to record in third person.
Thank you!