Sitecore ISE powershell inconsistent results

Question

I am running a script in Sitecore powershell to find items bases on a regular expression on a custom field ('Subkey'). This script sometimes shows results and sometimes shows 'No items available'.

Why is this not consistent? And how is this possible? I am running this within the Sitecore ISE

Write-Host "Begin script"

function Get-InvalidKeysAndSubkeys {
   #param([string]$label)
   Get-ChildItem  -Recurse | Where-Object { 
    (
     ((![string]::IsNullOrEmpty($_.Subkey)) -and ($_.Subkey -match "[^a-zA-Z0-9$ \-_\.!'()]"))       
     )
    }
  }
$x = Get-InvalidKeysAndSubkeys
$x | Show-ListView -Property Name,Key,SubKey,Id,ItemPath
Write-Host "End script"

Answer 1

You are missing one important parameter (-Path) when invoking Get-ChildItem:

Get-ChildItem  -Recurse

Fix this with something like this:

Get-ChildItem -Path "/sitecore/content" -Recurse

If you do not define -Path parameter your context item (start item for getting children) will be taken from item defined here

Answer 2

Turns out the problem was not having a

-Language

parameter for the Get-ChildItem call. Sometimes it would be evaluated for the correct language and sometimes not. Forcing the language fixed the problem :)