Interlocking Stones

I get "cannot be affected; weakened frame" when i cast this when soloing

And I just turned level 16, bought it, scribed it, and can't use it. Vender says it's a lvl 16 spell Can scribe it at level 16 Once Scribed it shows as a lvl 18 spell. It will let me put it on my cast bar. Casting it I get the message "Failed ability cast: Casters Level is Too low

they adjust the spell levels periodically when doing so, they forget to change things like tool tips, vendor lists, etc the choking thirst was another that was changed to a higher level but since it was accessible before, I had it before, had it on my spell bar, but was greyed out because they raised the level of it.... one day, they'll have all their ducks in a row....one day