If you are not using self-signed certificates for your computer certificate, IE you have a valid Intermediate and/or Root Certificate signed by a valid Certificate Authority:
Even if you remove this certificate from the Remote Desktop store, the next time someone remotes into that device, the RDP self-signed certificate will re-appear.
You need to use a wmic command to configure TerminalServices (RDP) to use your computer certificate.
From an administrative powershell window:
Get-ChildItem -Path Cert:\LocalMachine\My
Copy the thumbprint of the certificate your computer is issued
Paste it into the following command to tell windows to use this certificate instead of the default self-signed RDP certificate. Ensure there are no spaces in the thumbprint and make sure it is enclosed in quotes as follows:
wmic /namespace:\root\cimv2\TerminalServices PATH Win32_TSGeneralSetting Set SSLCertificateSHA1Hash="THUMBPRINT"
Even if the self-signed certificate shows back up in the Remote Desktop store, your computer will ignore it, and your findings for Plugins 51192 and 57582 will no longer show in your scans.