When approval workflow gets triggered for the supplier portal non-PO matched invoice?

Hi Everyone,

I am trying to create a non-PO matched invoice from the supplier portal, In their supplier needs to enter the requester email ID which needs to approve the invoice first. But when we submit this invoice from the supplier portal, no requester is getting approval notification based on the requester provided in the highlighted field below. Also in AP, this invoice is having approval status as Complete, and no Validation or update can be made. Is there any other step that needs to be completed for such nonPO match invoices?

Status of invoice in AP:

Please share your input.