That says to me, your caliper needs attention. Apparently, one side is not allowing the piston to move similarly to the opposite side. The 'sticky' side is causing more rotor wear.
Two things to check, disassemble the caliper, both sides, and install new O-rings/seals after cleaning up any corrosion in the piston bores, and on the pistons themselves, and then I suggest replacing the brake hose, ensuring the passages in the caliper are clear. The rear doesn't brake as-much as the front twin calipers/rotors do, but if you don't use the rear brake, your stopping distances will be longer. The VMax's longer wheelbase compared to a sportbike's shorter wheelbase means the rear brake can work to stop the bike while the sportbike is doing a 'stoppie,' w/the rear wheel off the pavement.