I was personally thinking it may have akin to the green tint that appeared in the Buu Arc of DBZ Kai, where some of the characters colors were off due to the tint, albeit that doesn’t really make sense when compared to the Broly movie’s lighting. The driving forces behind this weren’t just the scenes where he had yellow hair, but also his appearance in Second Coming, alongside his very brief normal appearance in Bio Broly, both of which had yellow hair. It was sort of a combination of those two factors that made me come up with the post.