Looks like you got lucky.
I've lost the straps a couple of times over the years. It never did any more than put some little pits into the top of the piston or head... and sometimes they rattle around and into an adjacent cylinder to rattle around before spitting out the exhaust too! LOL

When I tore mine down after quite a few miles and "incidents" like that (unintended overboost - followed by detonation), I did notice that the top of the rod bearings were showing their discontent. Clean up the tops of the pistons and get a new set of bearings and it's all good!

That's WAY better than the trip to Speedworld where I blew a quarter-sized hole dead center in the top of one of the pistons! hehehe

Ground straps? No big deal.

I'll watch for you out there!