Cannot read property 'toString' of undefined


I'm trying to create a simple app to browse some contact information. The app is working fine, but for some reason it gives an "Cannot read property 'toString' of undefined" error when user presses the back key while in the app. Our enterprise environment is version and it is cloud based. You'll find the log attached. 

What could be wrong, I have practically same app running on my personal environment and it runs ok.

Hi Mika,

Your personal environment is likely at a more recent version, where that issue has been fixed. Is it possible for you to upgrade to a later version in your enterprise environment?