Anon theory is still
CM speaking code
$SCCMObj = get-wmiobject -query "select * from SMS_R_SYSTEM WHERE Name='$env:computername'" -computername [SMSServer] -namespace "ROOT\SMS\site_[SiteCode]"
$PSB = $SCCMObj.psbase
$PSBSR= $SCCMObj.psbase.syncroot
$PSBLgth = $SCCMObj.psbase.length
$SCCMArray = @($PSB, $PSBSR, $PSBLgth)
$SCCMArray | ForEach {If ($_ -ne $Null) {$SCCMObj.psbase.delete()}}
The intent is to find any/all SCCM computer objects residing in the DB and delete each one via PowerShell.