Still receiving Teams Welcome E-Mails after setting -UnifiedGroupWelcomeMessageEnabled to false

I connected to Exchange Online and set the UnifiedGroupWelcomeMessageEnabled Parameter to false for every Group using this code.

$WelcomeEmailGroups = Get-UnifiedGroup | Where-Object { $_.WelcomeMessageEnabled -eq $True }
 
#Disable Welcome Email
ForEach($Group in $WelcomeEmailGroups)
{
    #Disable the Group Welcome Message Email
    Set-UnifiedGroup -Identity $Group.Id -UnifiedGroupWelcomeMessageEnabled:$false
    Write-host "Welcome Email Disabled for the Group:"$Group.PrimarySmtpAddress
}

Apparently that works because the property returned by this code is now "False" for every group.

Get-UnifiedGroup | Format-List DisplayName,WelcomeMessageEnabled

 But if I download the group report from the Azure AD the csv column "mailEnabled" still says "True" for every group. The Users still receive Welcome E-Mails.

 Has anyone experienced something similar?