Problem with molex connectors
Both manufacturers have assumed that whatever will be plugged into the other end of their connector will have both ground pins fitted &amp; connected together (usually a safe assumption).
They therefore assume that they can save 1 or 2c on each unit by only fitting 1 ground pin.
Unfortunately for you, they each picked a different pin to fit.
If you have any access to the back of one of the connectors, you may be able to gently tease the ground pin out of the hole its presently in (you may need to depress/bend some little tabs on the side of the pin) and fit it back into the other hole such that it now lines up with its mate in the other connector.