Quest doesn't complete

Date of issue:5/10/2022
Time of issue:21hs
Frequency: 4 times
World name: Alpha
Character name@Home World name: Alyx Ihri@alpha
Retainer name:
NPC name: Ultima weapon
Monster name:
Class/Level: white mage/ 56
Party or solo: party
In-game time:
Area and coordinates: Porta decumana dungeon
Housing:
Steps:
1. Following quest 'The ultimate weapon'
2. Do dungeon the porta decumana
3. Die before the last boss is killed and returned
4. Quest still asks me to confront the ultima weapon
5. Tried the same dungeon another 4 times and after the last boss is killed, I leave the dungeon but nothing happens. I cannot continue the quest. I cannot abandone it and take it again