I'm sure it's just an oversight, but...
"Gorm quickly unslung his harp and began playing a tune he’d written himself some years back, a lullaby he thought to call Sleep of the Petal Maidens. Hearing the ensorcelled notes through the din of combat, the pixies and naiads began to nod and blink drowsily; the distraction wasn’t enough to lull the fey to sleep, but it did slow them just long enough for Fola to shred the nearest of them with her magically controlled vines and send the others scurrying into the forest.
“Well done!” Gorm cried, dismissing his invisibility and stepping up beside Fola."
From Assault Formation:
https://paizo.com/community/blog/v5748dyo6shdb?Tales-of-Lost-Omens-Assault- Formation#discuss
Seems pretty hostile to me, surely enough to dismiss the invisibility.
Again, just an oversight.
The targeting of treants, and naiads by the heroic Pathfinders actually confuses me more, but I don't keep up with the gameworld politics, so...
Ha, I'm dumb!
I totally missed that.
I'm just gonna slink away now...