Classic Editor Woes

With the 5.6 update, the classic editor now shows a warning dialog when leaving a post or page and asks if I want to leave even though I just saved the post or page. Dismissing the warning or clicking updating a second time stops that dialog box from appearing.

Also, the theme we use “Risen” has always displayed a slider on the home page. The slider could contain an image or a video. Now the slider no longer appears. The author of the theme has ceased development and we were planning to update the site but now the choice of when has been taken away. If there’s a fix to return the slider, please let me know.

The page I need help with: [log in to see the link]