The Service Health graph on the Dashboard reports missed emails in the "Needs Attention" section for settings that are already enabled.
The Service Health portion of the dashboard reports emails that failed to detect.
Messages appear when a series of emails that normally are blocked are not due to another setting enabled.
For example, an email from [email protected] normally appears as a newsletter, but [email protected] is on the approved senders' list. This email still appears in the "Needs Attention" section under "Newsletter / Marketing" as an email that was detected but delivered anyway.
This behavior applies to all the rules that can affect the delivery of emails that otherwise are blocked. Settings like Approved and Blocked senders, Email Impersonation Control, Data Protection Policies, etc. affect how emails are handled.
The other purpose for the Service Health section is to alert of detections not currently enabled, which can help prevent spam in the future.