Outlook Items.Restrict Does not return all messages

I have a small powershell script, which uses Outlook interop to move certain messages from inbox to other folders. The basic move operation is done using the code below:

[Reflection.Assembly]::LoadWithPartialname("Microsoft.Office.Interop.Outlook") | Out-Null
$olFolders = "Microsoft.Office.Interop.Outlook.OlDefaultFolders" -as [type] 
$outlook = new-object -comobject outlook.applic开发者_高级运维ation
$namespace = $outlook.GetNameSpace("MAPI")
$inbox = $namespace.getDefaultFolder($olFolders::olFolderInbox)
$filter = "[SenderName] = 'Dummy Sender'"
$messages = $inbox.items.Restrict($filter)
$messages | % { 
    Write-Host "`t$($_.Subject)" 
    [void]$_.Move($destination) | Out-Null
}

The problem I'm noticing is that items.Restrict is not returning all matching messages. Each time I run the script, I get anywhere from 3 to 20 messages.

Has anyone observed this behavior before? Is there something obvious that I'm missing?

You are modifying the collection while you are still in the loop. either save the entry ids into a static array/list and then reopen the messages one at a time or use a loop from count down to 1.