When attempting to report a catch weight product as finished using the F&O form dependent on a production order, the quantity pending completion for the product is automatically entered as the catch weight quantity to be reported, and the quantity corresponding to the conversion for the product between the catch weight unit and the inventory unit, indicated in the released product field “Nominal quantity,” is entered as the inventory unit quantity. This is not happening on the production floor execution form, as when a catch weight quantity is informed on the corresponding field, inventory quantity doesn't get automatically filled with the conversion of the nominal quantity on the released product form.

This issue has been addressed in LCS#1045591 and PG provided explanation behind why it is intended "by-design".

However, PG encouraged us to raise an Idea for potential users who need this functionality instead of extending the code logic to fit their business scenarios.