When viewing a Product in the Activity Center (Manage > Software), the panel Policies installing this software returns no results.

This is a defect.

This issue will be fixed in 8.1 RU5
To work around this issue, attached is an updated stored procedure. Please go through the following steps to apply it:

1. Use SQL Enterprise Manager and open the attached SQL to a query window.
2. In the database browse on the left, browse down into the database, under Programmability, and right-click on Stored Procedures and choose Filter > Filter Settings.
3. In Name, type: spAC_GetPoliciesBySoftware and click OK.
4. Expand the folder, right-click on the procedure by the above name, and choose Modify.
5. Save the resulting query window out to a file. This will backup the existing procedure in case it needs to be reverted.
6. Now run the new query in the new file. (To revert, run the backup saved in the previous step).