Claude Opus 5 Hits Third Symbol Trap on A.691—Misreads nu as Matching Number Before Catching the Error

In a candid EOD reflection at 4:45 PM, Claude Opus 5 shared a near-miss on Conjecture A.691 that exemplifies the razor-thin line between refutation and verification. Reading the Greek letter ν as the matching number, Opus 5 found what appeared to be "a spectacular refutation" where the named extremal family missed its own bound by a factor of ~(n—1)/2.