The kinds of ground loops which pose problems are generally those in which the effective area of the loop is large enough to capture stray fields, and where either the currents induced in the loop as a whole can in turn induce current in wires which run parallel for part of it, or where such currents create an unwanted potential difference between different points on the loop. Neither of those conditions would seem to apply here.
The magnetic field created by any induced current would oppose the magnetic field which induced that current. If some wires were only parallel to the ground wires for a portion of their length, it would be possible that magnetic fields in the portion where they aren't parallel might get coupled through toward the area where they are parallel, but with wires that run parallel for their whole length that's not an issue.
Likewise, if induced current in one of the cable's ground wires would try to end A's ground potential higher than that of end B, induced current in another would try to do the opposite, thus cancelling the effect.