This is true, and I do find it somewhat frustrating. I read through the lumen 2022 presentation, and while I know they are doing filtering in order to make the surface cache not look distractingly bad, it’s still rather unacceptable from a reflections standpoint.
Of course, lumen working at all is a technological marvel, especially with the incredible performance demands of 60FPS games. Game art before real-time RT really couldn’t support smooth, non-leaky reflections like lumen can. For lower quality reflections though, I almost find it more helpful to think of lumen SF reflections as global parralax-correct cubemaps in terms of how you art around them.