>>42654442
Downloaded this. Tried "Mammaria" randomly, of course, and it works fine. No error.
>It's not all lorebooks
One thing this lorebook does is place its entry in the "World Info (After)" section. Most lorebooks don't bother and leave it in the (Before) part.
https://files.catbox.moe/gnjzb9.PNG
To check if that's the cause, test with:
https://momoura.neocities.org/preset/neoVORPUS.json
as your preset and see if it gives you an error.

If not, I believe it might be related to your preset and how it handles that.