Lots of explanations about this in lots of other threads, but basically, when you go to change your companion on record for the earlier flight, the already booked companion most likely loses their later flight.
You can try and protect the original/later-flight companion by booking a flight for them on points. After the earlier flight is flown, call in and change your companion, and change the point booking to a companion pass booking
Last edited by dmbolp; Jan 30, 2020 at 11:14 am