Flame Wall gem bugged

Hi i play a witch. After i selected "only cast" with weapon set 2 which was a ashen staff, i could no longer bind flame wall onto my skill bar. i had to delete the entire gem and cut another one for it to work. Appreciate if the team can look into this. Thank you.

I had the same problem. Frost wall level 9 works perfectly when bound to weapon set 1 chimeric chant gelid staff. I had ashen staff on set 2.
I then leveled up frost wall to 12 and then i couldn't equip this and it shows 'information currently unavailable'.