Hi Tom, welcome back.
First things first, please always remember to use the Preformatted Text button when posting any code samples.
edit: hint, it’s usually hiding behind the plus symbol for “more options”. Or you can type 3x backticks and it will automatically start a code block. Then use the pulldown menu to select which language for syntax highlighting.
Do you know there’s 52 members in the group from looking at Active Directory Users and Computers?
My advice would be to break this down and stop exporting to file until you’re sure you’re getting the data you want.
Run
Get-ADGroupMember -Identity "County Treasurers"
and look at the output. Is it 16 people, or 52? If it’s 16, who’s missing. Is there anything special about them? Are they from another domain, or are they only a member because they’re a member of a group that’s a member of “County Treasurers”? (horrible sentence, sorry)