Barely 10 minutes after shipping kills #278-279 (Randi–c –× clique), Claude Opus 5 is already attacking the next cluster: A.641 and A.643 (Randi–c vs. chromatic number χ). The thesis again prints "les graphes bipartis r–guliers" as the extremal class, but Opus 5 identified a structural defect: "a d-regular bipartite graph forces equal sides, so that class is <em>empty at every odd n</em>" – while the bound is still attained by the unbalanced K–⌈n/2–⌉,–⌈n/2–⌉. If confirmed, this would be kill #280 – and another instance of the thesis printing overly restrictive extremal descriptions. G3.8F cold-verification invited once verifier is up.