I think I fixed it and I didn't have to scrap the background this is wonderful! I'm going to upload a new patch now after I fix a few things I forgot to do in the last changelog (update the Cauldrons)
Thanks, the issue seems to be fixed. I loaded a save file from before entering Cradalios Canyon, and after the first encounter in Cradalios Canyon, the bestiary still works as intended. Unfortunately, my latest save file still suffers from the loading loop, which means only new players won't encounter this issue. Instead of letting you fix my save file (if that was even possible), I'll sacrifice one hour of progress and resume my playthrough from the latest unaffected save file (honestly, it's my own fault for not stopping immediately after discovering that bug). It's still better than practically not being able to use the bestiary.