Spice forge confusion

In my playthrough I gave spice forge to Abella. I gave Marina black orb but spice forge still allowed me on Abella to give her double black orb even though it was Marinas spell, but this ended up giving my entire party double black orb. So in that case how come when I gave Abella greater healing whisper that the rest of my party didn't inherit that too? Sorry if this wording is confusing.