UIView transition working one direction but not the other

I have two WKWebView objects that are subviews in my main view hierarchy. I'm very new to Swift so I don't know much, but I'm trying to transition between these two views and everything works perfectly except when I swipe to the right, the left swipe does the animation as expected but the right does nothing then snaps to the page.

func animateTranstion(fromLeft: Bool) {
   let webViewToShow: WKWebView
   let webViewToHide: WKWebView
   let transitionOption: UIView.AnimationOptions

   if fromLeft {
      webViewToShow = webViewB
      webViewToHide = webViewA
      transitionOption = .transitionCrossDissolve
   } else {
      webViewToShow = webViewA
      webViewToHide = webViewB
      transitionOption = .transitionCrossDissolve
   }

   guard webViewToHide.isHidden == false else {
      return
   }

   UIView.transition(with: webViewToShow, duration: 0.5, options: transitionOption, animations:) {
      webViewToShow.isHidden = false
   }) { _ in
      webViewToHide.isHidden = true
   }
}

I've tried using .alpha instead of .isHidden, I tried changing the duration and changing the animation, and even just hard coding the animation into the option. I followed the variables down to this function and all the objects are correct, it knows which to hide and show and where, but for whatever reason the animation just isn't happening?

UIView.transition(with: webViewToShow, duration: 0.5, options: transitionOption, animations:) {
     webViewToShow.isHidden = false 
     webViewToHide.isHidden = true
}) 

I ended up changing this function call and now the transition plays in both directions.