"New Email" form suggestions for "To:" field

Hi, I have a problem with the new email form when there is no email record in the document I am creating the email from. When I click into the To: field, some of the records are duplicated multiple times in the list and many of them don’t exist as contacts anymore and/or don’t have email addresses in their records.

Where does this list of suggestions come from? If it is a cache, how can I clear it? Thank you.

Installed Apps

ERPNext: v13.20.0 (version-13)

Frappe Framework: v13.20.0 (version-13)