I've recently been trying to set up my daughter up on the Windows 10 Xbox App so that she can talk to and play minecraft with her friends. The first account I created wouldn't show her gamertag when I logged into it on the Xbox.com website and I got the "uh oh you have found a glitch" message when I tried to change her xbox permissions.
I then deleted that Microsoft account and set up another one. I did this in an incognito window on google Chrome as I was trying to limit the access to any cookies on my computer which might associate with the old account. This appeared to work ok, but when I got to the stage of adjusting her permissions, the website crashed.
I then had to go through the whole process again using the same email address.
What happens now is, when I log into xbox.com using Chrome, it associates with the first gamertag ( when the website crashed). When I log in with Microsoft edge, it associates with the second gamertag!
The xbox.com app associates with the second gamertag, but although we can send messages to her friends, when we invite them to a Party, they don't get the invites.
I've never come across a system as buggy as this before, I've spent far too much time on this already!