I have tried to get this poi for three days now, and this event always bugs out and bars progress:
It’s “Use the priory’s bramble begone rifles to clear the brambles”, which clears the way to the plateau over Northwatch, where the PoI is. Every time I’ve tried to do it, the second vine just stays up, no matter how long you use the rifles on it. Big group, small group, there’s no difference.