Ok, I see that it shows 3.15 when first connected. Then, after a random amount of time, the bootloader then shows this other version even though the car is just sitting on the track the whole time? I see you're using the latest version of the v3 Bootloader, but can't see the dongle version. I assume that it also the latest version?
I tested on all of my cars fitted with Type C chips, and none of them ever changed what firmware version was showing. If you can find something that might be different for your set up, that might help. Make sure all the braids are nicely formed so that power does not fluctuate if the track is bumped. It looks like something moved on your video, right when the version changed, but that could have been coincidence.