Cant slot Conductivity anymore !!! help !!

I used Conductivity for most of the time, but yesterday something happened and it disappeared from my skill slots, i checked everything 100 times, there is no reason why it should not be working, i am playing storm weaver archmage and conductivity curse is one of my main dps for boss damage, basically now its a dead spell cant slot it, is there any fix for this or has anyone encountered same problem?

Same issue. Any luck?

The only way i found solving this is crafting a new skill gem and getting rid of the old one, luckily i did not upgrade it too much so it was an easy fix, but i see how this can become problematic for people who min max their gem skill