Tab Bar Controller doesn't update frames when hidden

I've been working on an application for about 8 months now, and have never had a problem with this until today. When I open up a specific page in my application, I need to hide the tab bar. However, ever since I switched to Xcode 9 - Beta, i've been having a problem that whenever the tab bar becomes hidden, it doesn't update the view to stretch to the edge. It just leaves a black space on the bottom of the screen.

tabBarController?.tabBar.isHidden = false

// This fixed the problem, but I never had to do this before. What else can be the cause of this problem
tabBarController?.tabBar.frame = cgRect.zero

This is what the page looks like when I hide the tab bar:

enter image description here

These are the attributes of my Tab Bar Controller: Tab Bar Controller Attributes