the last scene can not be unlocked - it looks like the variable sereevents is stuck at 7 (set in 01_quests_events::253), but the scene replay requires 9.
the events 7 to 9 are one long uninterrupted scene (starting in 01_sidequest::6871, as "label sere03_02"), you could either set the replay to serevents == 7 (and the next "real" event gets 8) or increase the variable in the two other subscenes/events ("label sere03_02_01" and "label sere03_02_02")