https://www.mcmod.cn/class/840.html
https://www.curseforge.com/minecraft/mc-mods/just-enough-characters
Forgive me for not knowing exactly who's fault it is, but the original JEI didn't have this problem, so I'm reporting it here.
Thanks for your work!

Any crash reports or logs?

I'm sorry I wasn't clear. JECh is a mod that allows Chinese players use pinyin(Chinese spelling style), but it doesn't work with your mod, no crash.

I'm not going to support JeCH unfortunately. If JeCh's devs or someone has time, they can explicitly support HEI because there are too many things I change pertaining search trees.