In reviewing the settings page of your Cloud Detector in the Enforce Server, under the section for "Policy Groups" there are no groups or policies listed.
This is true even when you have confirmed that a Policy Group is assigned via the UI.
When a cloud detector is configured on the Enforce system and multiple policy groups are associated to it, the Detector Details web page can show a blank list under certain conditions (multiple policy groups triggering the scrollable list), hiding the list of policy groups altogether.
There are no workarounds for this issue, but the defect was resolved with the release of 15.8 MP2.
It is described in the 15.8 MP2 Release Notes:
DLP-46353 | In the Enforce Server administration console, under certain
configuration conditions, the Detector Details page for cloud
detectors incorrectly displayed a blank policy group list.