2 Xbox at home - frequent disconnect on one of them

We have 2 Xbox One at home (one is One S , the other is One X)
We play with my son. He’s on the Xbox One S and does not see many disconnect issues.
But I get disconnection issues frequently on my Xbox One X.

I don’t have any issues with other online games.
And I don’t have issues when talking in the party (me and my son)
I have good bandwidth and zero quality issues on my uplink.

My Xbox Nat type is “open”

If I create a convoy, my son joins but we never see eachother.
If he creates a convoy, I join but we cant see eachother in the same session.

I would recommend to test with FH4 if the same issue occurs using gamepass for instance.

Depending on result you have 2 options :
https://support.forzamotorsport.net/hc/en-us/requests/new
https://support.xbox.com/

You can also add your post to the long list of Crashing issues and troubleshooting thread.

before yesterday we were playing FH4 already. with no issues…
Also, I already submitted a ticket.
I tried changing the teeredo port but that did not fix the issue…