it’s possible there is some firmware bug that causes it but i can’t think of a possible scenario. if it was just one scene then maybe something called the code that reinitializes a scene, but for all scenes to get erased - i can’t think how it could possibly happen.
another reason why a firmware bug would be unlikely is that it didn’t just erase all scenes but saved that to flash, since it’s still empty after a reboot. the only time tt saves empty scenes to flash is after updating firmware. that’s only done when you boot it up after you reflash firmware, that code doesn’t get called anywhere else.
so yeah, sounds like it might be a hardware issue. have you tried saving a scene and see if it’s still there after a power cycle?