Weird Tire Wear

Just rotated my tires yesterday, the left sides had about 6/32” of tread, while the right sides are at about 4/32”. Per the manual, I just switch the front and rear, do not cross tires to other side. I never saw even wear on front and rear on both sides, but different side to side. What do you guys think?
I have a platinum, at about 17k miles, I bought a set of 18” TRD OR wheels and tires that had like 10 miles on them. I know have about 55k on the truck, so just under 40k miles on wheels/tires.

 

How often did you rotate them?

 

If they are the oem tires, you’re lucky to get that many miles out of them. I wouldn’t be overly concerned with that little difference over 40k miles.

 

I do them every 5k with oil change

 

Yes, Michelin’s on factory rims. I suppose, just never seen that before…