I have an 8+ 256gb. After installing 11.4 last week, the system has become randomly unresponsive. For example, I press the home button and I feel the virtual "click" vibration but the screen doesn't wake up. Same thing for the power button, it freezes and won't respond to it. Other times if I'm at the home screen, it doesn't respond to tapping on icons. Then 10-20 seconds later it acts like it tried to do all of those click actions at one. It never did this before I installed 11.4, any ideas?