At startup or when prompting the app drawer, my wallpaper will suddenly switch to whatever elements I have on the rightmost screen, regardless of the screen I'm actually on. This also occasionally happens when returning to homescreen from another app, or when unlocking. If I begin scrolling to another screen, the appropriate elements suddenly appear.
Attached video shows the behavior with the app drawer, using a base pack preset and one of my simple custom presets. The other elements you see are just native widgets.
I'm on a Pixel 7, latest update, with Nova Prime. This doesn't happen on my other device (OnePlus 6), even when using the same presets. I've tried fresh install, direct touch/parallel rendering settings, different settings/adding pages in Nova, etc.