The reported date for an Attendance Rule Infraction and Threshold depends on when it is sent.
If the Infraction Type selected in the Attendance Rules and/or Threshold settings requires approval, the Conduct Manager must go to onRecord > Approval > Conduct and click on the Send button for it to be sent to the users with email access. Depending on when that task is completed will determine the Reported date for the Rule/Threshold Infraction.
If that Infraction Type does not require approval, then it is the Email Notification service that will determine the date - when it actually gets sent will be the date set on the Rule/Threshold Infraction. If for some reason the service is delayed, that can make the Reported date different from the triggering Infraction. That situation is more unusual and the majority of the time they will have the same date.