Acronis Cyber Cloud 8.0 Advanced edition and Acronis Backup Advanced 12.5 introduced Dynamic group feature (see details here).
You may face situation when content of dynamic group is not populated correctly (for example, you register a device that matches search criteria, but it is not added to the group).
Issue in the product.
This issue occurs when you create dynamic group based on the "osProductType" criterion (for example, osProductType = 'server')
Acronis development team is working on the issue; it will be fixed in future updates.
Meanwhile, please use other criteria for dynamic groups.