job timeout inconsistency

We have the attemptDurationSeconds set to 2 days, but the termination we got was 1 job at 2 days, 1 job at 6 days, 2 at 7 days. No other jobs were running during those 2~6 day period.

I know the doc says it's on a best-effort basis and not to expect accurate timing, but this is wild. Is there any way to determine whether this is just a hiccup? Should my effort goto writing something that sweeps and checks for job with duration longer than 2 days?