Budget - One way rentals from BOS

I need to rent a car from BOS, but return it to MHT. When I booked the flights I did a quick check and saw that this was possible. However, now that I am trying to book it, I can't :(

Sorry, but we don't allow rentals between those locations. Please change your entries and try again.

And yet, BOS-PVD one way is fine. :rolleyes:

Budget has some strange one-way quirks in general.