The infusion recipe requires a void metal plate, but I have not even learned about the Crimson Cult yet.

Edit: Version 2.1.2. I need to relaunch with 2.1.3 real quick

Oops, cannot reproduce in 2.1.3! I still see it in my book because I completed it before upgrading, but that's not on your end.

Spoke too soon.... I forgot that all that is needed to make the research available is seeing an Elytra...