Multiple Xbox One's showing in Devices

Is your son using your own (adult) account?

If so, do yourself a favor and create a separate account for your son with his own email.

There are so many parents in this forum, where the son went on a shopping spree with the unrestricted parent account, or where the parents later reconsider giving their kid access to their own email, and then all game progress can't be transferred over to
the new account of the kid.

The earlier your son has their own account, the better.

Has your console ever been in repair and has been replaced perhaps?

Thanks for your input. It has never been repaired.

I noticed that I do have more than 1 console, I know my account has been used on my GF xbox but there are like other 3 with the same serial number, I sent my console to repair services twice, is that the reason it is duplicated?

My son could have signed on to other consoles, not likely but definitely possible.