EM-5 focusing desaturation effect
I noticed the same effect when I did some test shots. There was a flexible tube with a consistent structure and some smooth parts. The structure was desaturated, the smooth part looked normal in the EVF.
If you once see it, you can easily repeat it. All you have to do is focusing on a regular structure..
I´m waiting for my seller to get a further body to prove if this is on my cam only or on every cam.