Is this happening for newly created POs? Or for a specific PO?

This applies to newly created PO when we fetch authorization,

we have ASL set up and active, if supplier is not found in approved supplier list, system trigger ASL but its trigger multiple times w. r t. number of lines.   

10 lines, it trigger 10 lines ASL authorizations steps 

@pramodka46 Now I understand. 

And yes, that is the system behavior we find. It has to do with ASL check being done for each PO line as the Purchase Group is fetched through the PO line. If for instance you have a PO line with different Purch Group, you wont get a auth corresponding to that line. 

If you try to approve every auth line, I understand it will not be convenient. However, ASL is in fact introduced to approve from a supplier level. So I suggest you to Approve the Supplier and fetch the auth rule to the PO again to get authorize conveniently. 

If your requirement is to authorize a specific line/PO out of the ASL list, then it will be an exception to the general expectation of ASL hence I guess the user will have to the high road of authorizing each line, or considering other authorization methods in IFS. 

However, if you have a specific business scenario, I suggest to raise this as an Idea. 

Thank you.