Not getting the decrypted OpenVPN Username from the Registry the same way that works for getting the decrypted Password

Question

I have a Powershell script that I am successfully using to get the decrypted OpenVPN Password stored in Registry.

This is the script that successfully fetches the stored OpenVPN Password from registry that too as decrypted string:

Add-Type -AssemblyName System.Core
Add-Type -AssemblyName System.Security
$keys = Get-ChildItem "HKCU:\Software\OpenVPN-GUI\configs"
$items = $keys | ForEach-Object {Get-ItemProperty $_.PsPath}

foreach ($item in $items)
{
  $encryptedbytes=$item.'auth-data'
  $entropy=$item.'entropy'
  $entropy=$entropy[0..(($entropy.Length)-2)]

  $decryptedbytes = [System.Security.Cryptography.ProtectedData]::Unprotect(
    $encryptedBytes,
    $entropy,
    [System.Security.Cryptography.DataProtectionScope]::CurrentUser)

  Write-Host ([System.Text.Encoding]::Unicode.GetString($decryptedbytes))
}

But if I do some modification to this for fetching the decrypted username from the same OpenVPN Registry section and using the correct key username like below, it doesn't fetch the decrypted Username:

Add-Type -AssemblyName System.Core
Add-Type -AssemblyName System.Security
$keys = Get-ChildItem "HKCU:\Software\OpenVPN-GUI\configs"
$items = $keys | ForEach-Object {Get-ItemProperty $_.PsPath}

foreach ($item in $items)
{
  $entropy=$item.'entropy'
  $username=$item.'username'
  $encryptedbytes=$item.'auth-data'
  $entropy=$entropy[0..(($entropy.Length)-2)]
  $username=$username[0..(($username.Length)-2)]

  $decryptedbytes = [System.Security.Cryptography.ProtectedData]::Unprotect(
    $encryptedBytes,
    $username,
    [System.Security.Cryptography.DataProtectionScope]::CurrentUser)

  Write-Host ([System.Text.Encoding]::Unicode.GetString($decryptedbytes))
}

Can anyone help out in knowing what am I doing wrong here and fix this ?