DisplayPromptAsync is unable to disallow suggestions in Xamarin on Android

Question

I have a working Xamarin Forms app for Android, UWP and one of these days, iOS.

I ask the user to type a userid in a DisplayPromptAsync() and I would like to disallow suggestions, which in this situation are unhelpful at best and counterproductive at worst. Below is the code. I pass keyboard flags with Suggestions not turned on, but Android still prompts for suggestions. What should I be doing differently?

Keyboard kb = Keyboard.Create(KeyboardFlags.CapitalizeCharacter);
string placeholderUser = String.IsNullOrEmpty(workingSystem.Userid) ? "userid" : workingSystem.Userid.Trim();
string defaultUser = String.IsNullOrEmpty(workingSystem.Userid) ? null : workingSystem.Userid.Trim();
string userid = await DisplayPromptAsync("Userid?", question, "OK", promptSkip, placeholderUser, 8, kb, defaultUser);