Tried to reproduce this bug using 2 accounts and the results were the same so probably it's not a "account thing".
After some research I've found that more users other than me are having the same issue, one of them even found a workaround. but it didn't work for me.

How to reproduce:
Go to "Setting>Profile>Unlink Microsoft account", check all the squares and press the "Unlink" button, it gives an error: "Yor account were not able to be unlinked. Maybe check you internet connection?" instead of unlinking your account.
I embeded a video of how to reproduce and a image of the error screen.