Is there some sort of bug in this quest? I can't figure out how to do what it asks.

SPOILER:

Quest text says:

Go to Sabrina's shrine in the evening and drink the Visionary's potion.

However no combination of meditating/drinking in the evening does anything, nor can I find a position that gives me a prompt to do so.

when you get to the shrine (backtrack trough harpies and turn left, I believe) it will show a message to come in the dusk/sundown. Do not drink the potion, but meditate to 21 or 23h (yeah, way after sundown) and then save - drink the potion and click on the shrine again... if it says 'come back in sundown', reload position where you did not drink the potion yet, meditate some more, and try again in an hour or two...

you could just bribe the priest, but trust me... you will never forget this quest xD

Funniest part so far