Problems with Powershell return value

I have a very simple powershell script. In a function is some logic and the return value of the function should be the exit code for the script. For the result 0 and 1 (ok and warning) the script works well, but if the function returns 2 (Error) I get no result in PRTG. The returned message is shown as "2 :2 RL disabled!" and the last value is empty! What is the reason for this behaviour? I hope it is reproducable for you.

The script:

[int]$retvalue = 0
[string]$retmsg = "Dummy"

function TestFunction()
{
	[int]$myretvalue=0
	$retmsg=""
	$countDisabled=2
	
	#... here comes some logic ...
	
	if($countDisabled -eq 0)	{ 
		$script:retmsg = "All enabled"
		$myretvalue = 0
	}
	else {
		$script:retmsg = ("{0} RL disabled") -f $countDisabled
		$myretvalue = 2 # 0 or 1 works, 2 not!
	}
	return $myretvalue
}

$retvalue=TestFunction

$output = ("{0} :{1}") -f $retvalue,$retmsg
Write-Host $output
exit $retvalue

custom-script-exe custom-sensor powershell script