Carbuncle unsummoned in Praetorium

When submitting a bug report, please use the below template and thoroughly fill out the necessary information.

Date & Time: Multiples. 12/7, 12/8, 12/9; various times.
Frequency: 100%
World name: Ultros
Character name: Hailenne Ganajai
Retainer name: N/A
NPC name: Carbuncle
Monster name: N/A
Class/Level: SMN 64-80
Party or solo: Roulette
In-game time: N/A
Area and coordinates: Praetorium Duty
Housing: N/A
Steps:
1. Queue MSQ Roulette as SMN
2. Successfully get Praetorium
3. Between the second Ultima Weapon fight and the Lahabrea fight Carbuncle is removed.

The chat window states carbuncle had been unsummoned or something along those lines. This means SMN has to spend the first couple seconds of the final fight summoning Carbuncle again which is incredibly inconvenient.

The rest of the fields were removed as they shouldn't have any bearing on this bug; though this is happening on PC, that shouldn't matter.