Hello and welcome to our forums,
This is the default behavior of the /ListOsLc command. If all build versions in the Windows 10 x64 launch condition are selected, the command will only display "Windows 10 x64". However, if at least one build version is not selected, all the checked builds will be listed individually.
Below is an example for the Windows 11 x64 launch condition:
- for Windows 11 x64, one build is unchecked.
- for Windows 10 x64, all build versions are selected, so it only displays "Windows 10 x64".

- OS launch condition.png (98.28 KiB) Viewed 3175 times
Most likely, in your project, Windows 10 versions prior to 1903 are not selected, which is why the command lists the individual build versions for Windows 10.
Let us know if you have any questions.
Best regards,
Liviu