The debounce assertion resolved the dispatched job's debounce window through
`prefetch_cached_from_handle`, which goes through the process-global
runnable-settings cache (shared by every test running concurrently in the
binary) and its tempdir-backed file I/O. Read the persisted rows directly from
the test's isolated DB instead, removing that cross-test coupling and extra I/O
from the assertion path. Still validates the full wiring
(handle -> runnable_settings -> debouncing_settings).
Co-authored-by: Claude Opus 4.8 (1M context) <noreply@anthropic.com>