This bug happened to me when I created an account, and it went like this:
- I already had a Google subscription in another site affiliate to the StackExchange network.
- I posted a question in physics anonymously, and posted using a hotmail address.
- I then realized the ocurred and tried registering on the site, trough the same Google e-mail. The website merged my two profiles in the two websites but the guest profile was still existing in separate.
- I tried answering the e-mail I received at my hotmail account for registration, but for some reason It did not created the hotmail account, and everytime I logged in trough hotmail account it logged into the gmail account.
Result: The 'guest account' was unregisterable and still remained 'guest' nomatter wich e-mail I used for login. As my account was not the questioner and I didnt had enough points I couldnt reply to anything. I had to contact an operator to merge the two accounts.