There is a code issue going on where the order of validation of fields is failing, when you change an email address.
Steps:
1. Login
2. Click Username tab
3. Click Edit
[ From here, this Account page, I suspect there is an issue with the whole code block validating the password initially.]
1. Type the current password
2. Change the email address.
3. Scroll down and click Save.
it will display "changes saved" but then shows the old email address.
New email address fails to update.