@John van de Waeter the solution for your problem is add unit FMX.VirtualKeyboard.iOS.pas to the project and comment out two lines near the bottom of the file, on "function TCocoaVirtualKeyboardService.HideVirtualKeyboard: Boolean;":
//if FTransient then // <- comment out this
// Exit(False); // <- and this
More info here: https://quality.embarcadero.com/browse/RSP-30045