Your ocean appears to jitter or chatter along
its horizon. If this occurs, you can smooth or filter the flickering
pixels along your ocean’s horizon.
To
filter your ocean along its horizon
In
the scene view, select the ocean that appears to jitter along its
horizon.
In
the Attribute Editor, select the
oceanShader tab.
In
the Ocean Attributes section, increase Horizon
Filter and then test render your ocean’s simulation.
Repeat this step until the jittering along your ocean’s horizon
disappears. See
Horizon Filter.