I have a very similar issue on the Xbox Series X when loading up a save slot, the console will sometimes will cut off the power. This is not a overheating issue. I tried power cycling my console, resetting the console, and reinstalling the console update, unfortunately the issues still exists. Playing other games doesn't cause the console to cut the power and it seems like during gameplay the power won't cut off also so I'm sure this isn't a issue with my consoles hardware.
No. This wasn't an issue before.