I had neglected to realize that some people are using their own background (sliders in the content for example).
The new system works way better if your background is set in the add-on (color, image, video), but not so great if your background is in the content tab.
If you’d like to email me (https://generatepress.com/account), I can send you a beta version I’ve been working on today.
It has an option in “Advanced Settings” that says “Background image inside content tab”.
Once that’s checked, it should work just like it did before.
Let me know 🙂