I'm not sure why you're getting duplicates. I can't recreate the issue, but I do have on idea as to how to workaround it in a slightly more elegant fashion.

get-help remove-distributiongroup | select -unique

Does that work?

I'm not sure why you're getting duplicates. I can't recreate the issue, but I do have on idea as to how to workaround it in a slightly more elegant fashion.

get-help remove-distributiongroup | select -unique

Does that work?

What does this return?

Test-Path -path "$pshome\Help.format.ps1xml"

This file contains the formatted views for MamlCommandHelpInfo objects that are returned by Get-Help.