Deep derived pure braids need not be 1-solvable

For every m at least 3 and every finite positive integer k, the kth ordinary derived subgroup of the classical disk pure braid group P_m contains a braid whose standard oriented closure is not integrally smoothly 1-solvable. Consequently P_m^(n+2) is not contained in F_n^m for every integer n at least 1. This answers negatively Question 3 of Shelly Harvey's contribution, joint work with JungHwan Park and Arunima Ray, Pure braids, Whitney towers, and 0-solvability, Oberwolfach Reports50/2017, printed3021/MFO PDF35, published2018. The witness may depend on the finite depth; no common braid in the intersection of all derived terms is asserted. P1 and P2 have trivial positive derived subgroups. The proof combines the established Gambaudo-Ghys ordinary closure-signature quasimorphism, its explicitly nonhomomorphic restriction to P3, and persistence through solvable derived quotients. Nonzero homogeneous signature is converted to nonzero ordinary signature by taking a power. The universal pointwise signature obstruction is proved from Otto's actual integral smooth solution definition using the signed cellular rank bound, integral universal coefficients, twisted surface classes, unit dual intersections and rank saturation, followed by Toffoli's surgery formula at -1 without an Alexander-root exclusion. The general quasimorphism facts are prior results: Calegari gives amenable rigidity, and Kawasaki-Kimura-Maruyama-Matsushita-Mimura2025Lemma7.12 proves a stronger defect-restriction identity. No new general group theorem is claimed. Bounded independent primary priority searches through October15,2026 did not establish an earlier complete answer to this precise braid-solvability question; no first-priority or continued-openness certification follows. The four-page unrefereed research note is accompanied by identical editable LaTeX/PDF, all44 unchanged original PR938 files, eight curated independent mathematical/source/reproducibility/priority/mechanism audit families, source-access records, and a closed-inventory standard-library POSIX release verifier. The original explicit104-letter braid in P3^(3) has closure signature -2, certified independently by a48-dimensional planar Goeritz form of inertia(23,25,0) and a104-term Burau-Meyer calculation. That finite witness proves n=1 only and is separate from the all-depth existential argument. Current replay requires Python3.10+ and os.O_NOFOLLOW; it authenticates copied bytes and compares complete exact saved mathematical outputs under an isolated nonoptimized worker. Preserved SymPy-based historical recovery suites have separate recorded replays. Finite controls are not universal proof, priority certificates or an operating-system sandbox. The immutable initial candidate records1/5; one newly developed complete stronger mechanism is separately recorded for a known combined2/5, with honest native reconciliation and no backdated historical invocation. AI tools were used extensively in research, proof development, source checking, computation, writing and adversarial review. AI-assisted checks are not independent human or journal peer review; neither such review nor formal proof-assistant certification is claimed. Raw third-party source bodies are not distributed.