Themes not applying wallpaper consistently on folding device

Changing the theme from one screen of a folding device only changes the wallpaper for that screen. Subsequently re-applying the same theme from the other screen does not fix the issue.

Reproduction steps:

1. With device closed, select a theme in Niagra settings

2. After applying the theme, open device.

3. Inner screen will have color, font, icon pack, etc. Applied, but not wallpaper

4. Reopen Niagra settings and apply the same theme

5. Wallpaper will not change

Also happens with inner/outer screens flipped (first apply on inner, will not change wallpaper on outer)

Workaround:

1. Apply desired theme to outer display

2. Unfold device, apply a different theme to the inner display. Outer display wallpaper will not change.

3. Apply desired theme to inner display. This changes the wallpaper of the inner display. Will not work without first doing step 2.