Different Files app behaviour on iPhone vs iPad

Dear Experts,

I am confused by what seems to be a difference in behaviour of the Files app on an iPhone compared to an iPad.

On the iPad, I seem to be able to view my app's Documents/ folder; on the iPhone, I can't. On the other hand I can access the app's iCloud documents on both devices.

Is this the expected behaviour? If so, what is the rationale?

Thanks, Phil.

To add another complication, I get different behaviour when I connect to the iPhone or iPad over USB and view the app's files with the Finder:

iPhone, Files app: doesn't view app's documents at all.

iPhone, Finder over USB: views the app's documents but won't open folders.

iPad, Files app: views the app's documents including contents of folder.

iPad, Finder over USB: views the app's documents but won't open folders.

Different Files app behaviour on iPhone vs iPad
 
 
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