Unsure if this is a bug or just a quirk of the order, but neither I nor my opponent were confident either way:
Played Harbor Village, followed by Overlord to play Wine Merchant. Our thought was we should get the +1 coin from Harbor Village because the Overlord RESULTED in getting +coins, but maybe it's because the Overlord isn't the one actually giving them?
Game 128946350
Yes, that is a situation that isn't so clear immediately.
But it wasn't the Overlord (next card played) that gave you the +$, it was the Wine Merchant. The same would be true if you replace Overlord with Throne Room.
Another example of Harbor Village 'not working' is with Boons. If you play a Boon giver after Harbor Village and you get one of the +$1 Boons, Harbor Village is also not giving your its +$1.