Frequent crashes during Ultimatum encounters (no error message)

I am experiencing random crashes during Ultimatum encounters. The game closes instantly to desktop without any error message, warning, or crash popup.

The crashes do not seem to be tied to any specific action, enemy type, or visual intensity. They occur unpredictably at different stages of the encounter, making it difficult to identify a clear trigger.

No consistent pattern or trigger identified
Only happens during Ultimatum encounters
No logs or error messages are shown
Issue is highly disruptive to gameplay