I have created FD order till pro-forma F8 invoice.
For some reason i had to reverse the goods issue directly (since pro-forma not allowed for cancellation)
As a result Delivery is open & again issued the goods (PGI)
As i try to do perform Pro-forma creation F8 system throws an error Item category is not relevant for billing but it was happening earlier with no errors
Note: It is happening for Batch items