With MAM_DELEGATION_PY=0 the monitor was left in the caller's process group (decision 2), on every restart the update makes. The legacy body now spawns it under job control (`set -m`, macOS has no setsid(1)) and restores the caller's option. The update tests assert the restarted monitor's PGID in both modes, and their teardown kills helper groups and this test's exact monitors instead of `pkill -f <ws>`, then reports anything left that names the workspace. Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>