Thats Cupping - I've not had any motorcycle I've owned do this but I've seen plenty of cars do this.
There can be a few different causes for this problem, all of which can translate to a motorcycle. If your tire isn't aligned correctly it can cause scrubbing, which is fairly easy to mess up if you're not careful with aligning the rear tire when you take it off. And the most likely cause of the problem is blown suspension. When your shock blows out you have no dampening and rely only on the spring which will cause that axle to bounce up and down and not have a constant contact patch causing certain areas of the tire to get hot while other sections remain cold, causing this "cupping" issue where the tire has these bounces every so often.
It could also be from a slipped belt within the tire itself.
Source: Trust me bro. No, I kid I was a mechanic for a few years. Now I'm just a shadetree one and I mess with motorcycle's fairly frequently. I hope my explanation of the issue makes a bit of sense for you and lets you know where you can look at for the problem. This isn't necessarily a tire issue, it's a suspension issue that has caused excessive wear on the tire itself. Also, replace that tire.
