Today I logged on into the Python issue tracker and suddenly I received duplicate notifications on posting comments to an existing issue.

The nice people over at Python quickly identified the problem for being that I got added to the nosy list twice, once by the login name and a second time by the email address I used when logging in and commenting upon the issue.

Looking at the account details it showed that the login name was changed to the email address instead of the one already registered in the database.