A failure of the DeTemple complete-monotonicity threshold

We refute the sufficient direction of Yang–Chu–Zhang Conjecture 1(ii) at a strictly positive parameter strictly below 155/294. The literal gamma/digamma quotient violates a positive-input midpoint inequality, hence its proposed negative is not completely monotone. The existential strictly interior source refutation is proved in Lean; the separately calculated rational witness is mathematical evidence, not the formal endpoint. Part (i) and an exact replacement threshold are not claimed. AI-assisted preprint by Myeongjin Kang, with no affiliation. Internal AI review is not external journal peer review. The accompanying Lean certificate covers the precise scoped main statement; inspect the formal endpoint, assumptions and provenance in the supporting package. Prior-art investigations are documented bounded searches, not worldwide-priority certification. Original prose is offered under CC BY 4.0 and original code/Lean under MIT; third-party rights and existing notices are preserved. The public supporting ZIP contains original proof sources and verification evidence, with bibliographic links and hashes instead of redistributed third-party source manuscripts. Recorded prior-art/source-access limits: Bounded independent prior-art screen; closest JMAA gamma-ratio remainder body remains paywalled; no worldwide-priority claim.