Testing on macOS, Chrome 59.0.3071.115.

I have the flag flipped to enable add to desktop

Pressing the 'Add to Home screen' button in Application > Manifest triggered the banner the first time it was pressed, but after I dismissed it and refreshed, the button now does nothing.

I assumed it would show each time I press the button, so long as the criteria are met, so this feels like a bug to me.