I have a 3k by 3k water plane. As I make adjustments to roughness and bump power, these "zones" square in shape begin to reveal themselves. It's areas where the math for the bump appears to alter. No amount of fiddling with Ray Epsilon will fix it. Is this a limitation of the software or a bug? I am using the Universal Material with Octane turbulence Texture. It works wonderfully in small sections.
I am "sort of" getting around this issue by plugging the texture in to roughness and lower the intensity to something usable. Removing it from bump completely. This does not have the same "look" as bump of course. But, it does offer some "break-up" of the water surface, at least.