Splitting out from my previous 'Apple Watch App Crashes' case which proved to be related to connecting an external Heart Rate Monitor like Polar H10- to Watch Bluetooth - Issue 'workaround' but not resolved but connecting H10 to iPhone Bluetooth during workouts
During the above case investigation I also highlighted that my Watch App would Crash if the Strength Training workout had 'Custom Exercises' in it as well as after the initial Sync it would then 'un-sync the custom exercises
After running the App for a week without a single crash, after connecting my Polar H10 to my iPhone instead of the Watch, Today was the first day I tried to run a saved workout with 'Custom Exercises', after 20 seconds the App crashed and then when I restarted I only had 5 exercises show instead of of the 8, which were still showing in the Phone App