Opened up both USB module types and noted an interesting thing. The type A has metal on both sides of the module. The type C has plastic cover on one side.
Also the A obviously has conductive strips that contact both top and bottom covers. So it is shielded somewhat from interference.
C does not have the conducive strips at all. So I wonder if the placement of the C type has varying effect due to the plastic cover (facing into the unit) and something causing interference.
Thoughts @nrp ?
FYI if anyone else tries to open a module, it feels like it’s glued down, but it’s not. It has tiny fingers on the sides. The cover slides off… Carefully.