Was able to get over it by starting the dungeon over again. For my side since I sided with the RDC I made sure not to touch any pylons. On your side I'd suggest not touching any pylons until after you talk with Galawain. But haven't done any repeated tests of this so could be just superstition on my part.
Overgrowth Quest Cannot be Turned In
in Pillars of Eternity II: Deadfire Technical Support (Spoiler Warning!)
Posted
Was able to get over it by starting the dungeon over again. For my side since I sided with the RDC I made sure not to touch any pylons. On your side I'd suggest not touching any pylons until after you talk with Galawain. But haven't done any repeated tests of this so could be just superstition on my part.