It's hard to tell from the Pict. if it is cupping one direction or the other.
Yes under inflation or overloading will cause this, as well as worn or improperly adjusted shocks. Also letting the tire sit in an oil stain in the drive/shed will swell the tire causing the same result.
You all have to keep in mind these scoots are built in a tiny factory using nothing more than bicycle jigs to clamp them together for robotic welders to tack them together. Take a real close look at where your frame attaches to your engine mount. I mean REAL close. You will see there is NO filler metal used in the weld. There is NO weld bridge between the frame, and engine mount. The metal is a Chromoly alloy that is simply melted together. To make it worse it is uni-directionally welded meaning it does walk or deflect during welding. Almost every one of our bikes have a tracking issue but most of us never realize it.
Set a makeshift cruise control, and find out.
I have had the worst luck w/ rear tires until I figured out the frame/engine mount alignment was off 3/16" from the factory. Those that knew me here years ago will tell you how many tires I went thru. In order to ride no hands I had to FIGHT the scoot way over to the left, and it was not comfortable at all.
Point is once I found the problem, and made my home spun alignment slot, and shims the bike tracks true, and the uneven tire wear has actually corrected itself, and taken the cup out of the tire.
The only way that I know to verify all this is a no hands ride. There is no other point of reference on the bike that can be trusted to be true because of the assembly methods used.
The goose neck or steering tube IS hand welded. Take a look at that, and then at the frame/engine mount, and it will be clear to you what I mean.