Partial Sales Returns Error

Im trying to make a Sales Return, 1 of 3 items over a previous invoice validated.

But when i trying to put -1 instead -3, im getting the error:

Row # 1: Serial No 001 does not match with Sales Invoice SINV-00056

But if i left the thre units, then it’s working.

But the customers only returns one of three items.

Another thing i did notice is: The default serials retrieved are not the same from the original invoice to be returned.