CoC 2nd weapon set: missing socketed skill

Using the same weapon set in 1 and 2 (locked), Cast on Critical says missing socketed skill in weapon set 2. No difference in spirit, and turning off other skills has no effect. Both boxes checked/reset.

Doesn't seem to reset with taking any of the gems in/out of inventory either, and other skills also don't make it activated (currently have comets, tried elemental weakness instead).

Any help appreciated, would rather not perfect jewel + quality up another CoC just to make it work.