There is no telling what is really installed on the target machine and we don't know what scan template you are using or if you are using the latest data files. The only/best way of troubleshooting issues like this is with logs and registry exports. Please create a case and attach the logs and registry exports from this article: DPDTrace command line logging tool used for patch detection issues Please zip all files into 1 zip files before attaching to the case.
You can create a case here: Support Portal
Please reference this post in the case so we can update this post once we figure out what is going on.