Stop Salesforce Email Notification to Queue Members

This is working as designed.

Administrators should create an internal email address to the Queue Email field in order to capture these emails or email notifications when queues or groups are referenced.

Notes:

• Creating Dummy/Fake email addresses can result in your organization's email being disabled until this is corrected due to email blocklisting.
• Email addresses should be verified and valid to receive these emails.
• If you must use an invalid email for anything in Salesforce, append ".invalid" at the end of the address. Any emails sent to a domain ending in ".invalid", will be discarded by our MTA. e.g. fakeemail@example.com.invalid.
• Emails, notifications, and reminders are only sent after tasks are reassigned from the queue to a specific user.

The Send Email to Queue Members alert will only work if the Administrator is using Case Assignment Rules and Active Assignment checkbox to move the Case to a Queue. If moving the case manually to a Queue or using a Workflow, the "Send Notification Email" checkbox should be checked for the alerts to be sent.