My tonearm must be wired out of phase

I have always had a slight channel imbalance with 2 cartridges and 2 phono stages.  The right channel always played slightly louder than the left and the sound stage leaned that way also, more center and right with the left stage almost nonexistent.  The meters on my monoblock amps also indicated less output on the left channel.

After switching the cartridge leads everything snapped into focus.  Full soundstage, 3 dimensional, amp meters equal and test record pink noise indicates equal balance as well.  My tonearm is a Basis Vector 4 with a captive cable.  Somewhere in the chain the wires must be crossed...that’s all I can come up with.  Anyone had this experience?