@BregBF Server Vendor is a property of a Hardware Inventory record, not of a Computer.
Hardware Inventory records are the physical servers used to run hypervisors, and are the hosts of virtualized computers.
In my implementation, Server Vendors contain data like “Dell Inc.”, and “LENOVO”, which are manufacturers of hardware, not operating systems. It is not the property you’re looking for.
You can tag computers running on Amazon cloud using the Fixlet Identify Computers on Public Clouds. Windows Virtual Machines have a property called “Computer Manufacturer - Windows” that you can configure in Computer Properties in BFI to import from BigFix.
So the next question is what is your use case for the information? Operating Systems are software, and in the Installed Software report, you can find the OS and its publisher.