It’s not an issue, it’s a bigger technical limitation no one in the rendering world has solved properly yet. Epic are probably closest to solving it out of everyone else in the rendering world, but it will still take a lot of time and research to get there.
WPO is just distortion of the rasterized buffers. It’s a postprocessing effect, not real 3D displacement like in offline 3D rendering engines. You can do that with rasterization, but not with ray tracing. You can not just simply postprocess/distort 3D geometry acceleration structure needed for ray tracing. That’s why no offline renderer has something like WPO that is fast and doesn’t cost any memory. So now, with introduction of ray tracing, Epic is crossing the line between rasterization and ray tracing, and these issues on the line between the two are becoming way more obvious.
I of course agree it would be great to have it solved. Just keep in mind that the reason this is not (properly) solved yet is not because they are not realizing how important it is, or because they are lazy or have different priorities. It’s simply because it’s a really, really hard problem to solve.