Strange wear pattern on drive belt

Going over the sling today getting ready for Sturgis ride and found this. Don't know how long it has been this way. No idea what is causing it but did find something interesting. Checked the front and rear sprockets but did not find anything that would cause it. No rocks or metal on the sprockets.

So, I jacked it up thinking maybe it would show up while running. Put it in first gear and saw this:

Sprocket wobble.MOV

Thanks but I love it too much! Just my OCD kicking in again.

I checked all the bolts on the angle drive and cross shaft and all are tight and torqued. The rear tire and wheel do not have any wobble in them so I am assuming the bearings are not the cause. The nut has never been loosened since I bought it and has not moved. I marked it early on and still can barely see the marks are still aligned. It may have been this way from the beginning for all I know. Never thought to jack it up and run it in gear. Maybe should have done that in the beginning. I don't hear any noise from the rear except for the belt rubbing the back pulley every now and then.

I don't have a 250 ft lb torque wrench so will have to locate one. I did put a 24" breaker bar and socket on the axle nut and couldn't budge it either way. Not that tells me anything other than it is not loose. Next thing I guess is to take the pulley off and have it checked to see if it is warped. Don't know if this is causing the belt wear. It is a bit odd that every tooth edge on the belt has the same wear mark and only on the passenger side. I really hate to start messing with the rear end components this close to taking a trip with it but then I would hate to see it has gotten worse by the time I get to S. Dakota.