app crash during step 25 of basic scenes tutorial

[Brodan]

When following along with the Basic Scenes tutorial, if you copy/paste properly and reach step 25, running the app is successful.

however, pressing the back button to close the app cause a crash:

I have not yet tested to see if this issue is resolved with some of the code later on in the post, but I feel that the app should be able to launch and close properly at this point in the tutorial before moving on

[Brodan]

update: it appears this issue persists once step 33 is reached as well