I receive on a iPhone 5s with iOS v8.1.2 the following messages in the Xcode console:
if it will help some one , i have this problem on cordova capacitor also , it was very strange for me until i remeber i put on css
*{
  -webkit-user-select: none;
  /* Safari */
  -moz-user-select: none;
  /* Firefox */
  -ms-user-select: none;
  /* IE10+/Edge */
  user-select: none;
  /* Standard */
}
yes it make keyboard have no access to fields also if you face same issue exactly : change * to div,span,img etc....
This is a known issue for several devices and Apple doesn't seem to want to fix it, as you said the keyboard you've requested still shows up and works properly. Filing a radar with apple is frequently the only thing you can do, then start hoping!
http://bugreport.apple.com/