From the docs about navigation (emphasis mine): 

> 
> However, using navigateUpFromSameTask() is suitable only when your app
>  is the owner of the current task (that is, the user began this task
>  from your app). **If that's not true and your activity was started in a
>  task that belongs to a different app**, then navigating Up should create
>  a new task that belongs to your app, which requires that you create a
>  new back stack.
> 
> 
> 

What are some examples of `your activity was started in a task that belongs to a different app`? I can only think of deep linking