Gamepass PC x Xbox

I have recently purchased the game pass on the PC assuming it would sync with my account on Xbox one, however it has come to my attention this isn't the case. The purchase that was made on the PC for the XGP* has not transferred over to my Xbox one.

Any takers as to why this might have been the case?

Firstly, I would assume and say the account the Game pass was bought on (1) was different to my Xbox account (2) and therefore Xbox have linked the purchase to the that account (1) rather than the Xbox account (2). This would make sense as the purchase would
have been linked to the initial payment account rather than the Xbox account where the Game pass has been applied.

If this is the case it is very weird.

My PC has the Game pass but my Xbox doesn't - They are the same accounts with Game pass applied.

There is nothing on the Xbox support section on this issue. I would greatly appreciate it if someone could clarify this.

Thank you in advance.

:)