Can't change Notification Sender address

When the domain is changed for and the sender details for notifications the system does not update the sending address when an actual request is opened. When the notification e-mail is received it still shows the old domain/email address and sender name, not the newly updated one even though it shows the correct info in the settings page.

Strangely though when replying to an assigned request the correct email/domain is used in the sender field, but when replying to a unassigned request it uses the old domain.email address and sender name.

Is there anywhere else the Sender Name & Email address needs to be changed than the E-Mail settings page? Or can I manually check what the settings are in a configuration file or something?

Thank you.