You could set up a campaign's mission control text (.mct) in which only one mission exists, such as "Surpise Reversed". If it never crashes, you know it's probably a mission-related problem. We do know that Enigma crashes occasionally, as do Patrol missions. Tirak has played hundreds of missions on his youtube channel with 2.563 and 2.564, so we have some data as far as stability...which is generally good.