I have noticed a bug in my phone that I have charged my phone full 100 percent. And after one restart it is showing 88 percent 

As you can see the last charge I have done is 3 min ago and screen time is 2 min and after a restart it is showing 88 percent ?? I need this answer and community raise this question please@NaveenYerradla@NipunMarya@RockyFTW