I think that particular one would be a prompting problem. Instagrammers and anime artists do left-right two-tone dyes all the time, so left-right two-tone rather than meshed gray blonde would be a reasonable interpretation of "half blond and grey hair" based on representations on Internet collected data.
I think the super-AGI should be able to figure this one out. This is the kind of things I would expect to have to think about when prompting a local 4B model, not the latest Sol or whatever is driving the image model here.
I don't think this ChatGPT's interpretation was necessarily wrong, given the prompt "Image of a middle aged man with half blond and grey hair". Maybe it should have asked back for clarification but that's it.
This to me as if someone is complaining for a basket full of extremely thin sliced fried potatoes for an order of "chips", rather than like wood and metalworking scraps.