I have seen quite a few bug entries related to this bug. It seems that there could be a simple solution in theory anyways. I would suggest not using the primary email address as the account anchor, which seems to be what is happening. It would seem like a better solution to let the user pick a random string of text/numbers to use as a login ID and tie that to the user account GUID or similar. This way, the users email address doesn't really matter that much, except for lost passwords, etc.
I have seen quite a few bug entries related to this bug. It seems that there could be a simple solution in theory anyways. I would suggest not using the primary email address as the account anchor, which seems to be what is happening. It would seem like a better solution to let the user pick a random string of text/numbers to use as a login ID and tie that to the user account GUID or similar. This way, the users email address doesn't really matter that much, except for lost passwords, etc.