That image gave me flashbacks of gnarly shader debugging I did once. IIRC, I was dividing by zero in some very rare branch of a fragment shader, and it caused those black tiles to flicker in and out of existence. Excruciatingly painful to debug on a GPU.
debugging in situations where there is no ability to halt and step, or in some cases even log, is extremely extremely tricky. Embedded is another domain where that's super common... or drivers or other peripherals.
there probably are tools these days for debugging shaders, potentially commercial packages if Nsight Studio doesn't have it, but yeah, that sort of thing isn't easy.
