Write-Verbose freezes PowerShell Workflow - powershell

Question

I just stumbled upon this strange behavior of PowerShell Workflows and now I'm curious if anyone else can reproduce the behavior and maybe even explain it to me.
To describe the situation I've created two workflows that are almost identical. The only difference is that the PSCredential object is created in the workflow scope in the first and in the inlinescript in the second.
First I define the Workflows with the following code:
workflow WorkflowCred
{
[cmdletbinding()]
Param()
$Password = 'test' | ConvertTo-SecureString -AsPlainText -Force
$Credential = New-Object -TypeName System.Management.Automation.PSCredential -ArgumentList 'test',$Password
InlineScript
{
Function Test-Verbose
{
[CmdletBinding()]
Param(
$Credential
)
Write-Output 'Start'
$Credential.GetType().FullName
Write-Verbose 'Testing'
Write-Output 'End'
}
Test-Verbose -Credential $Using:Credential
}
}
workflow InlineCred
{
[cmdletbinding()]
Param()
InlineScript
{
Function Test-Verbose
{
[CmdletBinding(
)]
Param(
$Credential
)
Write-Output 'Start'
$Credential.GetType().FullName
Write-Verbose 'Testing'
Write-Output 'End'
}
$Password = 'test' | ConvertTo-SecureString -AsPlainText -Force
$Credential = New-Object -TypeName System.Management.Automation.PSCredential -ArgumentList 'test',$Password
Test-Verbose -Credential $Credential
}
}
Now to the strangeness. I can run the following Three commands without any problem:
WorkflowCred
InlineCred
WorkflowCred -Verbose
But if I run the second workflow with -Verbose my console freezes until I hit CTRL+C??
InlineCred -Verbose
I can see this behavior if all of the following conditions are true:
I run a function from within an InlineScript (in a PowerShell Workflow)
One of the parameters are given an object of the type PSCredential as value
The PSCredential object is created within the inlinescript
The function is Writing to the Verbose stream
I've tried this in PowerShell version 3 and 4.