The startup restore relaunched linux-wallpaperengine for the last
selected wallpaper but never re-applied the still that Noctalia derives
its palette from, so colors after login came from whatever wallpaper the
shell restored on its own. Every other path that puts a wallpaper up
pairs launch() with syncPalette(); this one now does too.
Switching wallpapers away and back was the only way to correct it, since
that runs apply().
