Gem effects not working on trigger skills, cant use same effects on multiple gems

I've been buying a lot of gem effects mtx but noticed it wont allow me to use it on trigger skills such as spellslinger, I tried equipping the effect first (sanguine bone cage) then putting it back to spellslinger but its not being applied, please allow us to use it this way, I also have the bestial accelerated growth gem effect too but it only applies to one gem (I have the support gem equipped on both thrashing vine and entangle but only works with one), I like to spend money on the game but this much should be fixed as I believe that this is not intended (bug)