Scrolling / menu issues with WKWebView

https://www.youtube.com/watch?v=K_vBD6IJdpE

List of issues visible in this video, with time references:

0:05 - While the menu is open, the content view can be scrolled, then once the scroll has completed (0:11), it locks down and can no longer be scrolled.

0:12 - Some odd behavior with swipe gesture. The menu doesn't initially follow the swipe (presumably because the user was swiping up, first). It then, however, recognizes the swipe after the user has released the screen, and snaps closed.

0:20 - The content view can be scrolled, again. Once scrolled, it stops being scrollable (as it should be from the start (0:22))

WKWebView is definitely an improvement for this behavior, since prior to upgrading, the content view was always scrollable while the menu was open, and now it's just sometimes scrollable, but still not quite right.

Thoughts? Thanks.