Although stated in the bug fixes, going through a nether portal in a world that was created in a pre release version ONLY (worlds created in snapshots seem to be fine) the game still gets the crash report
"The game crashed whilst ticking player
Error: java.lang.NullPointerException: Ticking player"
Also the "Affects Version/s" field didn't seem to have an option for the pre releases or snapshots so I just had to say 1.15 ------ Sorry I just found the issue and I will make a bug report with the correct field info
Duplicate of MC-187408, read the moderator note on that ticket.