A rock or bolt got caught between the primary housing and front sprocket. It happens.
There is nothing for a loose belt to hit in there.

As mentioned you can run that belt for 100,000 miles and it will be fine.
It's when you have a cut at the edge of the belt that you would need to replace it.

That said, keep an eye on it.

 

Hi Guys

On a similar issue , i must have got a stone caught in the rear pulley recently . Probably when they were resurfacing the roads with tar and chipping dressing ( cheap method, let the traffic roll the chippings in ! Don't get me started). Anyhow I noticed a chip out of every fourth belt tooth. No chords cut or exposed and the belt surface is undamaged, however a bit of chrome plating has been worn off the rear pulley teeth in various places. Front pulley, from what I can see looks ok. The Tech at the local dealer thinks it will be fine, seen worse still running as is and just to keep an eye on it when I'm cleaning for any deterioration. I'm thinking that i'll have to replace the lot anyway rather than just the belt ( very expensive) so i'm planning on just running it until i'm off on a big trip when i'll have to dig deep . Guess I might as well replace IPB and Clutch bearing whilst everything would be coming apart anyway. What do you guys think , i'll try up loading the Photos.

 

I'd run it and start gathering the parts as per your message. Then change it before a big tour just for the piece of mind. Way cheaper to do that job in your own shop then pay a dealer in the middle of a tour.