New wheel and new rim tape. Almost certainly you have a tiny bit of spoke hole exposed. It doesn't take much. Take off your tire and tube and carefully examine your rim tape. If you can see the tiniest little arc of rim hole, that's it. When you pump up your tire you have 100 psi air pressure forcing the fragile inner tube against the sharp metal edge of that hole.

Realign your rim tape to cover it up and you'll be good-to-go.