We were having a similar problem on our project where the banding was occurring on our meshes, particularly the landscape. We fixed it by looking in the Default.ini and discovered that under the " [/Script/Engine.Engine] " there was 2 values for the “NearClipPlane” setting, with the latter setting it to a value that was way too low.
Changing this second “NearClipPlane” value to 10 fixed our issue, but any value between 3.0 and 15.0 will probably work and not break anything.
Hopefully this fix will work for you too.