I've come across a really weird problem. Right now I have a connector soldered to the pads on the Proto Backpack. If I use the provided headers, the pads don't have connection to the headers. If I use my own cable-as-a-header, the pads work properly.
Is this an issue with the Proto Backpack itself, or what? I tried the other proto backpacks and headers I have and they al present the same problem.
P.S. The headers are NOT soldered to the proto backpack, just stacked.