By your description, I can think of only 3 possible reasons. Please check the following possibilities:
1) There are times that the spriter scml plugin when updating scml objects produces a bug. For example, when you update a scml object and the spriter images of the object are in a family or vice versa, then the spriter images/ objects are mistakenly accepted in the spriter object family. If you have this problem then the app will surely crash on gameplay.
To diagnose this install a beta release of C2 and if an error message shows when you open your .capx then this is causing the crash. To fix this, you need to read the error message to find out.
2) When an infinite loop / a function leading to a new function and etc. / repetition of trigger are used, they don't give out warnings of crash of game since it is not an error but just a misuse of events.
The unfortunate part of this is that it doesn't crash immediately, and will only crash when the events are triggered or true/active.
3) The most common cause of crash on-start of app / during gameplay are plugin errors on app build. For example , if you have admob, Inappbrowser, IAP plugins or any third party plugins and when these plugins are incompatible with your app or if the plugins are not well set or incompatible then a crash will happen.
Well, I hope you find the cause of your problem.