In GFI LanGuard installed updates / patches for Linux and MAC computers will not be displayed under Patches tab, but these will be displayed under the Software tab instead.
For Linux / Unix computers:
Here is an example for a patch apt-transport-https-1.0.1ubuntu2.4.1 show as missing in the GFI LanGuard scan:
After a remediation it will be displayed in the Software tab:
For MAC computers:
Each installed update / patch is not shown. Instead, under the Software tab it shows the most recent version of the base software that was patched.