I’ve been meaning to log this same issue too.
Its separate from Bug: Zwift crashes if you edit an imported workout (TrainingPeaks)
If your experience is the same as mine then by “Large workout”, it seems to be when the workout has over a certain number of intervals/segments in it - I find this a problem particularly if I am using a workout that I’ve created in a workout editor such as TrainingDay.com and then imported to Zwift using the “paste into folder” method in operating system file manager.
Workouts with a large number of segments it doesn’t seem happy with, it really struggles to load them and then crashes/closes out as you describe.
You’ve reminded me of another bug with workout editing too, but I’ll log that separately.