Can do! Happy to.
So, lumen generates global illumination through a series of world-space caches feeding a screen-space final gather. What that means is that a simplified version of your scene is created by lumen, and that’s what’s actually generating your GI. If your lumen scene is missing large amounts of data that your primary view has, you’ll see it as weird lighting discontinuities. You’ll want to go into viewmode, lumen, and choose ‘surface cache’. That will show you all the scene objects that the surface cache can’t represent in pink, and all the scene objects that it won’t represent for memory reasons in yellow.
That jittering initially looks to me like screen-space artifacts. Would you try r.Lumen.Reflections.ScreenTraces 0 and r.Lumen.ScreenProbeGather.ScreenTraces 0, to remove screen-space lighting and see what the lumen scene alone is telling you?