Purchase recipt -> "% Amount Billed" not working for purchase return and Purchase invoice return/debit note

Hi Community
I have created a purchase return against a purchase received and expect “% Amount billed” get changed accordingly in more information section but it does not changed.

Steps to follow

Step 1: Created a purchase Recipt(without any purchase order) for item Mentha Oil quntitiy 300 rate 100.(% Amount billed in More information Section is 0% As Expected)

Step 2 : created purchase invoice against this purchase receipt for Item mentha Oil Quantity 100 rate 100(In Purchase receipt % Amount billed in More information Section is 33.33% As Expected)

Step 3 . Now we have 200 litere of mentha oil remaining to be billed from this remaining 200 I have make Purchase receipt return of 100 (In Original {first ,Master}Purchase receipt % Amount billed in More information Section is still 33.33% while I have returned 100 litre so it should be 50%)

Also in report “Received Items To Be Billed” it is not showing row for purchase return .

Please suggest If i am doing it correctly or it is really a bug.
Is there any workaround against this ??

For Purchase invoice return/Debit note
Step 4 : make a new Purchase invoice for 100 litre “% amount billed”(in Purchase recipt) is 66% as expected
Step 5 : Make a debit note/Purcahse return of 100 litre “% amount billed”(in Purchase recipt) is still 66% which is expected as 33%

Please use this table for replicate

Step Doctype quanity Rate amount % Amount Billed(Expected) in Purchase recipt % Amount Billed(Actual) in Purchase recipt Result
Step1 Purchase Recipt 300 1 300 0 0 OK
Step2 Purchase Invoice1 100 1 100 33.30% 33.30% OK
Step3 purchase invoice 2 100 1 100 66.60% 66.60% OK
Step4 Purchase Invoice Return/Debit Note 100 1 100 33.30% 66.60% Incoorect
Step5 Purchase Recipt Return 100 1 100 50% 66.60% Incoorect

Created a ERPNext issue
https://github.com/frappe/erpnext/issues/19530