[wheelie_boy]

This could explain why it might not have shown up in testing.

It's not just that the image had a non-sRGB colorspace, it's also that the pixel values in this specific image were out of the expected range.

[jfkebwjsbx]

"Out of expected range" values should be the very first thing to test for...

[OJFord]

And maybe it was; maybe the colour space aspect also was.

Testing combinations of edges is not so common/obvious.