What happened to our cable is that it was damaged in transit. The mini end of our XLR cable somehow got into the open end of the cable, bending a pin slightly. I gave the renter (who had shot Scarlet before), specific instructions on plugging in all the cables, but when he tried to insert a slightly damaged cable, bad things happened. We are trying to safeguard ourselves against accidental damage if we decide to rent out for a second time. And as this thread has been mostly useless, I was attempting to provide information for others to do the same.
And yes, I did settle with my renter for a replacement. Thanks for the lecture ... That's not what my complaints are about.