Hmm. Maybe it's a 1am reset and not a 24 hour reset?
Though I'm pretty sure I tried it the next morning.
I don't know, but what I can tell you is that the airbnb gift card program is very new, and a lot of the stuff they are kinda figuring out as they go along, so I don't think some/all of the rules are hard coded/set in stone (YMMV)