Hey Bill, saw your post and definitely think your assumption is right where the damage could have come from.
As I understood the bike once fallen to the left onto the luggage box right? That could have been the starting point of the damage, as the force of the impact when it fell had to go somewhere, even you didn't see any obvious damages right after....

By the time it could become loose and moving and at the end it got broken....

Be happy that the exhaust system is reliable and kept you up straight... haha.

Anyway, if you start a trip like this damages will occur and have to be calculated as you probably did it already. When I went through Vietnam I had also issues and damages but it was always a nice challenge to fix them and get back on the road...

Wish you good luck and save ride.....

@Shuben... so the "Gummikuh" is back in operation already?

BR
Dave