I've had my Samsung Galaxy S6 for around 16 months now. It seems like over the past 3-4 months the battery life has gotten worse, I've experienced a weird problem a few times too. Today, I was surprised look at my phone and see that the battery life was much lower than it should have been, since I had not been using my phone, it had just been in my pocket. Looking at the battery life chart in settings confirmed that there was a sudden drop in battery life a couple hours ago.
Why would this happen? I was not in an area without service, I was just doing errands in places that have good to excellent cell reception. I understand when you have no service, or very poor service, the battery will drain quickly as the phone struggles to find a signal, that didn't happen today.
What is using the media server service? Why is the screen usage at 43%?