so I have this set up for whenever a seed is in my storage it gets imported into a composter with a filtered basic inventory hopper
but remove the composter while in use and it will crash the server (in this case, haven't tried in single player)

this is how the composter is set

and this is the part of the logs where it crashed
crash_log_trim.txt
this happened with the 1.6.6 fabric version

I can confirm this is also happening on 1.6.8