Seen like that? Even my boss said this's new problem and said wow,
Boss was hopeful it was signal quality but it is not.

That annoying pattern is present in all inputs including tuner.

Whole screen of herringbone pattern get finer and coraser pitch with
time and switching among different input does this also. Herringbone
pattern slopes from top then do a zig then zag back to same slant to
countinue down to the bottom. The middle zig-zag band doesn't move up
or down.

Came in under warranty.

I have photos. Did bit of research and got some little info.

Cheers,

Wizard