On a server version 1.37.4:
Spawning Gaia fight II goes good until the mob spawning phase and after the client crash.

I can log back in and finish the fight.
Tried only once. The difficulty ramps up and it is owning me hard.

Log attached :
crash-2024-05-05_21.19.53-client.txt

Thank you for the report! I will try to fix this too!