You've shown the time the cover view is added, but not the time it was removed.
How long did a user take between putting the app into the app switcher (or background), and bringing it back to active? How long between those NSLogs?
You're giving us piecemeal information here, making it difficult to help you.
Also, note that I added an else to where you're checking for a nil. That's important, because if coverView isn't nil at that time, then it's not going to create the view.
Add logging to every bit that's relevant.
Topic:
UI Frameworks
SubTopic:
UIKit