Okay, so I just loaded up with all of angels and bobs, and it seems that you Can research it, just the nickel and invar processing techs are missing, thus not listed as requirements.
You Would technically still have to research advanced invar smelting (from angel's smelting) in order to acquire the invar plates that are still used in the recipe, it's just not a dependency for the technology. I'll add a tech dependency for it, unless you have proof that it's actually not working in-game. I've tried both with and without angel's smelting.
