Can you debug the DS_ReceiveEmails microflow, and verify the number of emails in the EmailList?
I suspect that the issue is in the configuration of the module - what to do with messages after they have been downloaded. If you take no action the email remains on the mail server and is then processed multiple times.
In the configuration, you either need to set it to delete the message after downloading, or move it out of the Inbox to a different folder ir you wish to keep a copy on the mail server