Error with Add-Member in Get-GitStatus on PowerShell Core beta.9 on Windows 10

[rkeithhill]

System Details

• posh-git version/path: 0.7.1 ~\Documents\PowerShell\Modules\posh-git\0.7.1
• PowerShell version: 6.0.0-beta.9
• Git version: 2.14.2.windows.2
• Operating system name and version: Windows 10 FCU (1709)

Issue Description

I am experiencing a problem with...
Executing Get-GitStatus is emitting a non-terminating error:

C:\Users\Keith\GitHub\rkeithhill\PowerShell [master ↓44 +1 ~0 -0 !]> Get-GitStatus
Add-Member : Cannot add a member with the name "Added" because a member with that name already exists. To overwrite
the member anyway, add the Force parameter to your command.
At C:\Users\Keith\Documents\PowerShell\Modules\posh-git\0.7.1\GitUtils.ps1:298 char:13
+             Add-Member -PassThru NoteProperty Added    $indexAdded.To ...
+             ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
    + CategoryInfo          : InvalidOperation: (:PSObject) [Add-Member], InvalidOperationException
    + FullyQualifiedErrorId : MemberAlreadyExists,Microsoft.PowerShell.Commands.AddMemberCommand