2nd copy of a spell in spellslinger cannot use MTX

example i chose being ember fusillade.
main ember fusillade can use MTX without issues.

a second equipped ember fusillade copy (in spellslinger) is not being detected for application of MTX. and yes ofc i have two copies of the same MTX.
not saying im requesting a refund ofc, but if you can circumvent the ONLY ONE COPY PER SKILL limit using spellslinger, you should also be able to use another copy of the MTX on it.