Just my best guess. I suspected suspension setup, because they are mid/rear engine cars, and yes, the weight is towards the rear, so you'd think it would just go. Probably some combination of road condition, tire temp, and maybe even tire wear. Or, something might have let go in the rear end suspension, unnoticed, but that's beyond my knowledge/experience/diagnostic skill of the C8 rear suspension assembly and parts. Try an internet search for "what causes rear end hop during hard acceleration from a stop?". Might give you some ideas. Try it on "Tour"?
I may have "a dog in this fight" soon, so I'm interested.