I don’t know if this has been mentioned before, but there is a glitch in The Shallows when clearing the Pestilence. First, when you try to clear the last couple of enemies when the bar is really low and you kill them, the bar will suddenly fill back up to about 90-95% full, but you will be down to your last couple of enemies. Second, when you clear the enemies and The Pestilence creature spawns, the skull will spawn, but when you go to the location, the enemy doesn’t spawn. I have a video for the second glitch but not the first glitch and I don’t know if there’s a way to attach it here in the forum. The only solution to this is to clear another Pestilence area first and then travel back to The Shallows later.
Hopefully this glitch can be fixed. It is a bit annoying. 
Thank you!