I haven't seen this covered but it sure seems like a major bug to me. I was asked for my aple password to finish up the installation of iOS 10. Voice over should have spoken the keyboard on that screen. It did not, I only heard the sound effect as I moved my finger around the screen. I did not have a braille display which would have solved the problem. I had to use a sighted friend to input my password. I don't know if apple accessibility is aware of this situation. But, if not, I will certainly tell them.
this also happened to my twin brother and to Jonathan Mosen's wife bonnie and there were probably others as well.