I had a wheel set built with Velocity Dyads. When I got the rims, I looked them over and didn't see any problems. Then a mechanic friend built the wheels. I trust his wheel building, and I remember him looking over the rims for any problems (he worked at Velocity inspecting rims for a bit).

However, months pass, and I'm finally building the bicycle that go with this wheels, and putting rim tape on... when I notice that both rims have some sort of dark, slightly raised areas inside the beat seat in one place on both rims. It looks like glue but feels like metal. Is this just a normal manufacturing issue for rims?