I think that is it, a precision error. I was reading a paper on ray tracing, and watched an old NVidia video about it, and one of the primary challenges in ray tracing is precision. It’s not efficient to continuously trace a massive number of rays from every possible source to every possible target (e.g., surface to surface reflection), so mathematical formulae are used to functionally get a similar / same result with a limited number of traced rays. It’s probably a problem with tracing rays from the camera to a certain distance from the camera at ‘parallel’ type angles because the formulas used are not sufficient to complete the render. Is the water + reflections on it in games like Battlefield V and Star Wars Battlefront 2 done via ray tracing? If so, I wonder whether the flickering occurred to those initially, and how it was resolved.