unable to see old assets after email change

One of our websites had an issue, described as below:

... User was accessing the system using old@gmail.com. She had some issues with that id and she edited her profile on CMS and changed it to new@gmail.com While the system allows her to login using her new email address, she is unable to see the assets assigned to her as editor in the new id. Even when she creates an asset, even though she logs in with her new email, the asset gets created under her old email id ...

Solution was:

In the users table of the Postgres database, only the "email" field is editable by users - now updated the "username" field to
new@gmail.com
from
old@gmail.com

(The updating of username field by users is not enabled since back-end changes to the CMS data sheet are needed when such a change happens.)