P4210 does not throw error when quantity is not entered

P4210 and P42101 does not throw error when quantity is not entered for a non-stock item having the line type 'N'. Instead, it takes the quantity as 0 and calculates the extended price assuming that the quantity as 1. However, quantity field is still blank.

Could you please confirm if the system considers quantity as 1 (internally), when the quantity is not entered even though the quantity field displays blank value in P4210 or P42101.

Request you to help on this. Thank you.