Does anyone have an update on this? I'm facing the same issue. It's even worse that only a few of my users get this error. It works fine for me and most of my users, so I can't even verify if a fix works.

Found this answer: https://stackoverflow.com/a/51414692/8355412 So basically, I only need to premultiply alpha to each of my rgb component

Strange thing, I tried setting my container view (just a UIView) background color from white to black, and walaa, it can render the color. This got me thinking if Metal or iOS in general does some sort of color snapping? so when the background is white and the color is "light" enough, it "snaps" to white? Any idea?

I tried that too, it shows the color normally on a black background. Digging into the vertices, color data looks correct as well