It doesn't happen every time I charge my battery to full but does happen pretty often. It will stay on 100% all day. I have only had this phone a month and has happened 10 times. Then when I plug in in to charge it won't charge. The only way to fix it is to power off and restart.
I am not rooted and use the stock battery indicator which I had to turn on under Settings / Power Saver / Battery Percentage.
I am not rooted and use the stock battery indicator which I had to turn on under Settings / Power Saver / Battery Percentage.