Accept AD Guest invite is not working if user has Live account

Hi everybody,

I know, there are plenty of threads about issues on guest invitations but I couldn't find anything specific about this issue we are facing, yet (maybe I'm just blind 😉 😞

We are inviting a user from our Azure AD (through Graph API).

If the user has an organizational account from another tenant, he is logging in and everything is fine --> fine.

If the user has no organizational account and no live account, he will receive a login through code mail verification --> fine.

If the user has no organizational account but a live account (home, xbox live, old skype, ...) he receives an error when clicking on accept that an account with this email already exists.

Bad thing: there is no way to login with your home account, you only can select another email address (which will not work on this invitation anyway).