how to prevent sync of nested array object between controller and component in ember

I am working on Ember.js 2.12.0

How to prevent sync of nested array object between controller and component.

For ember string its working but for nested array object its not working.

below is ember twiddle link

ember twiddle

In twiddle if you change the value of String and arr and click to HOME route and again come to ABOUT route then you can see that value of String gets changed but the value of arr is not gets changed

Thanks in advance for help.