Cast on elemental ailment gem not working for some reason

Dear master

I have working with this gem properly and smoothly during past days but just now i switched to my 2nd set of weapon and somehow it stopped working anymore. I have enough spirit (more than 100) but it kept saying that i missed sockedted skill, while i have a comet gem in the supported sockect. Please kindly have a check and fix it asap as it really influence my game experience. Thank you.

While i switch my weapons from set 1 to set 2, the gem work properly in my new set, namely set 2. but if i switch the set back to 1 with the same weapons, it won't work again.