Created date and Modified date is inconsistent for Report in Advanced reporting.
1: Modified date format is not consistent
2: Showing Created date is greater than modified date.
The current behavior with Created Date VS Modified Date is expected, as the Created Date is updated when a resource is imported into the server from other instance or previous version, while the Modified Date will remain unchanged.
However this behavior is understandably confusing to some users, and therefor we already have an enhancement request on our internal tracker to change it, and have the Modified Date get updated when resources are imported.