The Bookwyrm is unable to cast a projectile-fell-amplifyx4 spell on blazing archwood trees on my tree farm. I have plenty of source jars for it to draw from. The other wyrms are casting their spells fine just not the one with the fell spell. mod version is 1.16.5-1.24.19

Hello,
This is likely due to chunk claims. You need to add Ars Nouveau and Minecraft as allys to your chunk claim, or enable Fake Players.

I'm having the exact same issue. I have Fake Players enabled and in my test world where I'm trying this, I haven't claimed any chunks. Grow and pickup work fine, but Fell refuses to work.