latest.log head / tail (~52k lines)
https://gnomebot.dev/paste/mclogs/7FXdKdW

Latest 1.21.1 changes I pushed which will be release as a update soon seems to fix this issue

Incompatibility with Excessive Building
Temp Solution:
https://www.curseforge.com/minecraft/mc-mods/feature-recycler

should this be reported to them?

Probably both of us yes then just post the link to each issue so they are linked