As you can see, the box for the list on the right doesn’t fully surround the cards. But if you move the list on the right at all, then the box will fix itself and surround the cards as expected. I initially was going to post that the cards weren’t being put into the box because of the rendering being buggy here.
Notably, this rendering issue actually shows up across refreshes, or doing the copy-paste in a browser tab and then opening the desktop or iPhone app. Moving the list anywhere fixes it everywhere.