After having attempted to modify the enchantability values of bone/flint tools, I've discovered that the obsidian hammer in particular seems to be assigned "athenaeum:FLINT" rather than "athenaeum:OBSIDIAN", which is what the rest of the obsidian tools appear to be assigned.
This issue occurs on the latest version, Pyrotech 1.4.33. I used Apotheosis to modify enchantability values.

Oof. Yeah...

https://github.com/codetaylor/pyrotech-1.12/blob/master/src/main/java/com/codetaylor/mc/pyrotech/modules/core/item/ItemObsidianHammer.java#L16

I'll fix it soon.

btw your link in the changelog to this issue goes to the wrong repository