Cast On Crit non-functional on specific weapon set - cannot fix

After re-speccing some points to accomadate a new amulet, my Cast on Crit stopped working on weapon set 1, giving the error "Missing Socketed Skill"
It still works on weapon set 2.

I checked both the skill and the cast on independently, both are active on both sets.
I checked my stats, satisfies both cast on crit and the socketed skill (Bonecage).
I relaunched the game, still broken.
I entered a new instance, still broken.
I tried a new skill and a new cast on crit, still broken on set 1.

Eventually I fully mirrored my tree so that the old weapon set 1 was mapped to weapon set 2 and vice versa. It is still non-functional on weapon set 1, but still works on weapon set 2 - so its unrelated to the tree.

I put my old amulet back on, still broken.

Something is very clearly wrong here, and I'm not sure my character can be fixed - it almost made it unplayable.

Definitely something to look into if possible, this could brick some characters.

Just to add, the spirit requirement is also satisfied on both sets equally - incase that was the assumption.

Also intelligence is the same on both sets (151). only stat that changes is dex - increasing by 10 on set 1.