From Android 9.0 one has the option of replacing the Home, Back and Open Apps buttons with a Back Button and a new Home button that, when slid left or right, toggles between open apps. In 5.6, sliding that new home button opens all the apps vertically and freezes the app panes instead of toggling them.
@RG_Durishin Having exactly the same problem on my LG V40. Hadn't figured it was related to MSL until I saw your post. Just swapped back to the native LG launcher and the task switcher is now opening the apps horizontally (properly) and no longer freezing.
Oh cool! Yep! Hope you are well, as well! Looking to upgrade my Galaxy S8+. Think I'm going to go with the Note 9 though after the Note 10 comes out so I can get a good deal. Good phones are so crazy expensive now.