I have 3 monitors, the left-most one is positioned vertically, the middle one is my primary monitor, and then a cheapy 1080p 19" on the right.

The right monitor seems to have the wallpaper reset completely every time (i.e., the standard out-of-the-box wallpaper is shown). The left and middle ones will sometimes have the out-of-the-box wallpaper, other times they'll just be swapped, or even sometimes I think it shows the wallpaper that should be on the right-most monitor. It seems like those two monitors can have any combination of the 4 wallpapers.

I have 3 custom wallpapers that fit my monitor layout with a sort of gradient effect that spans across all 3 displays - it looks pretty cool when I set it manually after boot up each time.

Is there anyway to control this?

I'm using KDE Neon on the latest build. Using 4.9RC kernel and tried several 4.8 and 4.6 versions as well (that doesn't seem significant). This has been an ongoing problem since I started using Neon about 4 months back. KDE Plasma 5.8.90, KDE Framework 5.29.0, QT 5.7.0. Intel GPU i915.

Thanks