can anyone explain this account problem to me?

The xbix app still in netabthat could be why

Its how you have it set it. At some point in time you might have had your preferences set up as such. I always get emails through my email associated with my Microsoft account when i add games and things like that.

I think it might be a bug or some type of malicious in Microsoft. As I'm getting the same message from Xbox live to claim my perks, i haven't opened anything but i have downloaded a couple games through game pass. But I've deleted all my messages n associated
games through game but i think about 5 or 6 times all my messages encluding that xbox live messages came back. So im still trying trying figure out whats up with it. So your not the only one who's console or Xbox/Microsoft account is messing up.

Your best bet here would be to log into
https://account.microsoft.com/billing/orders to see which one the purchase was made on. I would also recommend making sure that you're logged into the PC and signed in to both the Beta App and Xbox Companion App with the same account.

It's probably due to contact preferences you have set. Just because you get an email on account b doesn't mean the game is on account b. Whenever I purchase a game, I always get an email to my other email instead of my Xbox account email. It's how I set
it up.