Exclude hidden mailboxes from a Dynamic Distribution Group

Another interesting finding I made thanks to an Expert Exchange question I was involved with.

The question sounded pretty simply

I can create new dynamic distribution groups using powershell and the Exchange Console, but I cannot figure out how to filter the hidden mailboxes so they are not added.

I logically started by trying to use the msExchHideFromAddressLists attribute trying to get the list of mailboxes where it is set to false using the following powershell script to create the Dynamic Distribution List

New-DynamicDistributionGroup -Name "test" -OrganizationalUnit 'mydomain/Distribution Groups' -RecipientContainer mydomain -RecipientFilter { recipienttype -eq 'usermailbox' -and HiddenfromAddresslistsEnabled -eq $false}

But I was surprised to noticed it didn't work! It was actually returning only mailboxes the ones hidden from the address lists. There was something wrong in my OPATH query but wasn't able to find out what up front...

To double check I was not missing something I tried creating another DDG with the same command as above just with HiddenfromAddresslistsEnabled -eq $true and both groups where giving exactly the same results! Here is the full powershell command I used to create test1

New-DynamicDistributionGroup -Name "test1" -OrganizationalUnit 'mydomain/Distribution Groups' -RecipientContainer mydomain -RecipientFilter { recipienttype -eq 'usermailbox' -and HiddenfromAddresslistsEnabled -eq $true}

That was pretty weird !