Delegated PO approval notifications not respecting the email sender address setup

Hello,
Delegated PO approval notifications are not respecting the email sender address setup.
In BPM Worklist > Task Configuration > DocumentApproval > Notifications , we have setup the following:

• Email: From and Reply To address: "puchaseorders@three.com"
• Email "From:" Display Name: "Workflow Mailer"
  When testing PO approval notifications, we are observing the following:
  • For non-delegated approvals: emails are coming correctly
    Display Name: Workflow Mailer
    Sender: puchaseorders@three.com)
    Example: PO 426013377
  • For delegated approvals, emails are not coming as expected, for the display name it's using the original approver instead of the defined Workflow Mailer
    Display Name: Sebestyen Pal
    Sender: puchaseorders@three.com)
    Example: PO 426013378