Can't enter four-digit Apple TV passcode discretely with iPhone

With Restrictions turned on for my Apple TV 4K (and my other Apple TV 4th Generation for that matter), when the Apple TV prompts me for the passcode based access of a restricted app or content, the Apple TV Remote app on my iPhone does not pull up the onscreen keyboard for entry of the 4 digits on the phone. It requires onscreen selection and entry of the numbers for the four-digit passcode (which makes the passcode obvious to anyone sitting in the room because it beeps and the selected number has an animated motion). Previously I had been able to use entry via the Apple TV Remote app with its onscreen keyboard to keep my small children from learning the passcode (the dots filled in on the screen as the numbers were entered but no visual indicator of what digit had been typed appeared on screen). Now I have to make them leave the room to be sure that they are not peeking between fingers. Other keyboard entry via the phone (i.e. typing into a search bar) and other functions of the iOS app still work normally.

Screen text at time of problem when restricted app is clicked to open:

Enter Passcode

Enter your four-digit passcode

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I have restarted the iPhone and Apple TV and even deleted and reinstalled/repaired the Apple TV Remote app. The Apple TV software is up to date (tvOS 12.1.1). My wife's iPhone with the app installed also no longer works (and worked in the desired way previously). I have re-opened the app while the screen is up, made the selection with the iOS app, etc. I have even tried the Apple TV remote app from the Control Center.

Is there a way to discretely enter this passcode from an iPhone (or even a bluetooth keyboard) to keep the Parental Controls passcode secure?