Xbox series s randomly turning on

My son has an Xbox series s that he just got a little over a month ago. The past few days the console will randomly turn on after being shut down. “Instant on mode” is turned off, So the console should be completely shutting down. But for some reason after a few minutes it will power back on. He has a cooling stand, mouse and keyboard hooked up to it. I also have a USB hub connected and an HDMI splitter. I have gone through and unplugged each one by one to see if maybe something is sending a signal to the Xbox telling it to turn on with no luck solving it. Anybody have any ideas or insight on what’s going on?