A second caller could get a part object half built, before its path and cache dependencies were set; that failed CI as os.path.exists(None). The fix registers an object only once its factory has finished.
From the Grok pain-radar digests, Oct 28-29 2026 (Oct 28 8:41 AM ET through Oct 29 early-morning Haitch editions). Verified live 2026-10-29: issue/PR read; title and state confirmed.