base 1.20.1 fabric instance
only mods installed are fabric api, moonlight lib, and supplementaries (2.5.22)

crash-2023-08-11_19.04.52-server.txt
latest.log

can be reproduced by going into a world and placing ash so that they fall
third placement leads to a crash

fixed

can confirm we have similar crash reports: https://mclo.gs/uxIulBr

Also, whichever player activates the crash, the server will always crash once the player logs in again _(likely because when there is ash nearby that is being ticked once player joins)_

My minecraft crashes without even placing ash
https://mclo.gs/I8xYWdz

Probably since lava and wood can generate close together.