I've owned a lot of 4X4 ATVs (some w/front diff locks) and one other SxS (X3) that had larger OEM wheels and tires in the rear than the fronts. You couldn't rotate them (wheels or tires).
My TRE is the first 4x4 I've owned that had different sized OEM wheels with the same size tires. I have to assume the difference in tire diameters is negligible and the engineers knew what they were doing because it works. And, I have the option to rotate the tires which I've never had before on any ATV/SxS. There might some genius there? IDK
But, I would like to know what Polaris engineers, and whoever wrote the owners manual, were thinking on a lot of s***! And whoever's responsible for quality assurance at the Mexico assembly plant, leave him at the bar sucking on cerveza because that conversation won't end well. (Lean Six Sigma?)