Status: Preprint submitted for peer review (March 2026). Abstract: We report the design, execution, and outcome of a three-part numerical audit program applied to the bounded oscillatory near-core regime (Regime III) of a regularized black-hole interior with a saturating scalar closure 1, 3. The audit addresses three questions: (1) Is there evidence for proper-time chirp—asymptotic growth of the physical oscillation frequency as measured along the central worldline? (2) Is there evidence for a late-time Regime III→IV drift toward a classical effective remnant-like state? (3) What is the practical amplitude boundary of the robust Regime III domain? For question (1), we define a gauge-aware proper-time half-period sequence from successive central equipartition crossings weighted by the central lapse, prove that terminal chirp is equivalent to the vanishing of these intervals, and execute a preregistered long-run audit on the primary run A0 = 0.0425. The primary marker remained qualitatively decreasing, but the preregistered evidentiary threshold was not met and control channels did not provide supportive agreement. The chirp result is ambiguity-limited; no manuscript-defensible positive chirp claim is supported. For question (2), the late-time diagnostics on the same run find that, within the defensible lapse-quality window, the dynamics is persistently bounded oscillatory Regime III. Apparent freezing-like behavior appears only after lapse-quality failure and is classified as a gauge artifact. No defended Regime III→IV drift is established. For question (3), a controlled amplitude-family scan identifies a robust Regime III zone (A0 ∈ 0.04000, 0.04275), a marginal strip (A0 ∈ 0.04300, 0.04525), and a lapse-limited zone (A0 ≥ 0.04550), with the robust-to-marginal crossover bracketed to a narrow interval near A0 ≈ 0.043. This boundary structure is the strongest positive result of the audit. Series Context: This manuscript is Part IV of a self-contained, four-part investigation into the effective dynamics of asymptotic density saturation in general relativity: Paper I: Singularity Resolution from Density Saturation: An Effective Framework for Bounce Cosmology and Regular Black Holes. Paper II: Cosmological Predictions of Asymptotic Density Saturation: Bounce, Inflation, and Dark Sector Phenomenology. Paper III: Constraint-Consistent Numerical Tests of Core Regularization in Scalar Field Collapse. Paper IV: Proper-Time Diagnostics for Regular Black-Hole Cores: Chirp Criterion, Regime Persistence, and Amplitude Boundary. Version History / Changelog (v1.0): Initial preprint submission detailing the diagnostic framework and executed audit outcomes for the proper-time chirp criterion, regime persistence, and amplitude boundaries.
Michał Jerzy Drewnisz (Mon,) studied this question.