Reset-ItemField failing silently

Question

I'm (trying to) using Reset-ItemField to remove broken workflow links. While no error is shown in the console, the relevant fields are not changed.

$counter = 0

Get-Item -Path :master -Query "/sitecore/content//*[@__Workflow = '{f1fb8a76-9c0e-fcbb-3f7f-a57c84e92e39}']" |
 ForEach-Object {
    Write-Host "Workflow " $_["__Workflow"]
    Write-Host "Workflow state " $_["__Workflow state"]
    Write-Host "Default workflow " $_["__Default workflow"]
    Reset-ItemField -Item $_ -Name @("__Workflow", "__Workflow state", "__Default workflow")

    Write-Host "Workflow " $_["__Workflow"]
    Write-Host "Workflow state " $_["__Workflow state"]
    Write-Host "Default workflow " $_["__Default workflow"]

    Write-Host "Broken workflow link found and removed from " + $_.Paths.FullPath
    $counter++
    if ($counter -gt 0) {
        break
    }
}

UPDATE 1

As Mark mentioned it is necessary to include the -IncludeStandardFields parameter when modifying workflow via Reset-ItemField.

What I have found so far is that I can modify the default Sitecore homepage item (/sitecore/content/Home) using with the following script:

$homeItem = Get-Item -Path :master -Query "/sitecore/content/Home"
Reset-ItemField -Item $homeItem -IncludeStandardFields -Name @("__Workflow", "__Workflow state", "__Default workflow") 

This proves that SPE is not broken in this environment. It also implies that the issue here is either to do with the way I am retrieving items (using Get-Item with a query) or is to do with permissions on the items retrieved by my original query. It is strange, however, that there is no warning or error message when the cmdlet fails to update items. I have also tried wrapping the update foreach loop with a using block with a SecurityDisabler New-UsingBlock(New-Object -TypeName "Sitecore.SecurityModel.SecurityDisabler").

UPDATE 2

After attempting to manually clear the workflow fields, I realised that there is some item:saved handler, or similar, which is re-assigning the workflow after the item is saved. This confirms that there is no problem with SPE or the script and there is no failure (or silent failure). I neglected to mention that the solution uses Sitecore Commerce Engine and I suspect there is some item:saved handler which is reassigning the workflow after an item is saved.

Answer 1

I had something similar just a couple of weeks ago. I ended up solving it like this:

$contentItems = Get-ChildItem master:\content -Recurse
ForEach($item in $contentItems)
{
    $item.Editing.BeginEdit()
    $item["__Default Workflow"] = $null
    $item["__Lock"] = $null
    $item["__Workflow State"] = $null
    $item["__Workflow"] = $null
    $item.Editing.EndEdit() | Out-Null
    Write-Host "Processing " $item.FullPath
}
Write-Host "All Done!"

For Reset-ItemField to work, I suspect you may need to add -IncludeStandardFields as an argument. This is required for any fields that are included in Sitecore's Standard Template.