Paul,
I had the same issue with my Cyclone. Yours is a 1/4" difference where mine were/are 3/8" & 5/16" (tri-axle). The dealer says they called Heartland/Lippert for Warranty Authorization and were told these axles measurements were within specs.
I have my suspicions regarding the Dealer's service department so I intend to have the alignment adjusted prior to having new rubber mounted up. With 6 tires it'll take a while to save up for that! There is an alignment shop here in town specializing in RVs & medium to heavy duty trucks.
I would give your dealer a chance as in my experience it was "he said/she said". BTW - This dealer in no longer a member of the Heartland family.
I heard some good excuses though; "You can't measure between tires as the air pressure may be different in just one that will mess up the measurements." "One of the tires may have more tread than the others so the measurements may be off."
Measure axle to axle and these "excuses" are discounted.
Give your guys a chance or contact the frame folks for the direct answer.
Dave G.