Another day, another flight ... At T-80 hrs, Row 4 didn't open up. Instead Row 4 through to 10 became blocked (as per EF) and all seats in the same rows 4-10 correspondingly "occupied" as per the QF seat diagram. EF shows only a few seats actually occupied - seemingly the same ones that were selected before T-80.
This was for a weekday 18:30 flight MEL - SYD.