Hexes don't apply properly if you didn't apply the status yourself, instead, the target is choosable, and when selected with the appropriate hex, your momentum is taken, your fp is taken, and the move does -nothing-.
I'm assuming it's meant to proc the hex, yes?
You'll have to provide more details.
The example in this case was a teammate applying silence to the target, then when I went to use Strangling Etacof, it allowed me to to no effect.
Bumping as this is still occuring.
To clarify, it allows teammates of the inflictor who have the qualifying hex to use the hex in question on targets that they themselves did not inflict, and when they select the target and confirm, the momentum and fp are spent, and nothing happens.
I.E. Person a inflicts person b with Silence, person c is person a's teammate, and goes to use Strangling Etacof on person b. They're able to do so, but when they do, the hex isn't placed on person b and their turn is wasted.