After reviewing the materials used in the F1/M1 connectors, it makes me suspect that lowered conductivity/high resistance may be the culprit. Those connectors are made with beryllium copper, platinum, and palladium, all of which are poor conductors compared to copper, gold, silver or even high-cu brass.
The late ( and *highly* respected ) Bob Crump always stood for the ACME.
With psychic power and primal intensity,