I’ve not seen this mentioned, but that’s probably I haven’t looked deeply enough.
I have now bought another Spark, sold the first one in May, stupid decision! So was looking at the position of my mobile, Samsung galaxy note 8, with it in the lower, using the built in arms, I found in my first Spark, I kept touching the screen with the edge of my hand as I moved it up to activate the various buttons on the controller, this brought about interruptions to the DJI app functions.
I decided to buy the rcgeek metal, better than plastic imho, holder and now I can place it above the controller without interfering with the screen.
I consider this a much safer way of using the controller with a mobil, how have you found using yours?