Missed jobs run at next fire time instead of immediately

Author: mesvamCreated Dec 24, 2025Updated Dec 25, 2025

Labelsbug

Things to check first

I have checked that my issue does not already have a solution in the FAQ
I have searched the existing issues and didn't find my bug already reported there
I have checked that my bug is still present in the latest release

Version

3.11.1

What happened?

I'm not sure if this is intended behavior, so I don't know whether to call this a bug or a feature request, you tell me...

When a job runs past the next fire time, it doesn't run again immediately after the previous run finishes. Instead the next fire time gets reset, even with misfire_grace_time=None, and the job runs on it's original schedule regardless of whether or not a run was missed

Here's a minimal example with AsyncIOScheduler. The task takes 3 seconds, but the trigger interval is 2 seconds.

python

from apscheduler.schedulers.asyncio import AsyncIOScheduler
import asyncio

# setup logging
import logging
logger = logging.getLogger()
handler = logging.StreamHandler()
handler.setFormatter(logging.Formatter('%(asctime)s %(name)s/%(levelname)s: %(message)s'))
logger.addHandler(handler)
logger.setLevel(logging.NOTSET)

async def job():
    logger.info('job start')
    await asyncio.sleep(3)
    logger.info('job end')

with asyncio.Runner() as runner:
    loop = runner.get_loop()
    scheduler = AsyncIOScheduler(event_loop=loop)
    scheduler.add_job(job, 'interval', seconds=2, misfire_grace_time=None, coalesce=True)
    scheduler.start()
    logger.info('scheduler start')
    loop.run_forever()

And here's the log output

2025-12-24 00:17:12,219 asyncio/DEBUG: Using proactor: IocpProactor
2025-12-24 00:17:12,221 tzlocal/DEBUG: Looking up time zone info from registry
2025-12-24 00:17:12,222 apscheduler.scheduler/INFO: Adding job tentatively -- it will be properly scheduled when the scheduler starts
2025-12-24 00:17:12,223 apscheduler.scheduler/INFO: Added job "job" to job store "default"
2025-12-24 00:17:12,223 apscheduler.scheduler/INFO: Scheduler started
2025-12-24 00:17:12,223 root/INFO: scheduler start
2025-12-24 00:17:12,224 apscheduler.scheduler/DEBUG: Looking for jobs to run
2025-12-24 00:17:12,224 apscheduler.scheduler/DEBUG: Next wakeup is due at 2025-12-24 00:17:14.222133-05:00 (in 1.997824 seconds)
2025-12-24 00:17:14,231 apscheduler.scheduler/DEBUG: Looking for jobs to run
2025-12-24 00:17:14,232 apscheduler.scheduler/DEBUG: Next wakeup is due at 2025-12-24 00:17:16.222133-05:00 (in 1.989867 seconds)
2025-12-24 00:17:14,232 apscheduler.executors.default/INFO: Running job "job (trigger: interval[0:00:02], next run at: 2025-12-24 00:17:16 EST)" (scheduled at 2025-12-24 00:17:14.222133-05:00)
2025-12-24 00:17:14,232 root/INFO: job start
2025-12-24 00:17:16,234 apscheduler.scheduler/DEBUG: Looking for jobs to run
2025-12-24 00:17:16,235 apscheduler.scheduler/WARNING: Execution of job "job (trigger: interval[0:00:02], next run at: 2025-12-24 00:17:16 EST)" skipped: maximum number of running instances reached (1)
2025-12-24 00:17:16,235 apscheduler.scheduler/DEBUG: Next wakeup is due at 2025-12-24 00:17:18.222133-05:00 (in 1.986747 seconds)
2025-12-24 00:17:17,237 root/INFO: job end
2025-12-24 00:17:17,237 apscheduler.executors.default/INFO: Job "job (trigger: interval[0:00:02], next run at: 2025-12-24 00:17:18 EST)" executed successfully
2025-12-24 00:17:18,236 apscheduler.scheduler/DEBUG: Looking for jobs to run
2025-12-24 00:17:18,237 apscheduler.scheduler/DEBUG: Next wakeup is due at 2025-12-24 00:17:20.222133-05:00 (in 1.984534 seconds)
2025-12-24 00:17:18,238 apscheduler.executors.default/INFO: Running job "job (trigger: interval[0:00:02], next run at: 2025-12-24 00:17:20 EST)" (scheduled at 2025-12-24 00:17:18.222133-05:00)
2025-12-24 00:17:18,239 root/INFO: job start
2025-12-24 00:17:20,229 apscheduler.scheduler/DEBUG: Looking for jobs to run
2025-12-24 00:17:20,230 apscheduler.scheduler/WARNING: Execution of job "job (trigger: interval[0:00:02], next run at: 2025-12-24 00:17:20 EST)" skipped: maximum number of running instances reached (1)
2025-12-24 00:17:20,231 apscheduler.scheduler/DEBUG: Next wakeup is due at 2025-12-24 00:17:22.222133-05:00 (in 1.990791 seconds)
2025-12-24 00:17:21,255 root/INFO: job end
2025-12-24 00:17:21,255 apscheduler.executors.default/INFO: Job "job (trigger: interval[0:00:02], next run at: 2025-12-24 00:17:22 EST)" executed successfully
2025-12-24 00:17:22,236 apscheduler.scheduler/DEBUG: Looking for jobs to run
2025-12-24 00:17:22,236 apscheduler.scheduler/DEBUG: Next wakeup is due at 2025-12-24 00:17:24.222133-05:00 (in 1.985206 seconds)
2025-12-24 00:17:22,237 apscheduler.executors.default/INFO: Running job "job (trigger: interval[0:00:02], next run at: 2025-12-24 00:17:24 EST)" (scheduled at 2025-12-24 00:17:22.222133-05:00)
2025-12-24 00:17:22,237 root/INFO: job start
2025-12-24 00:17:24,223 apscheduler.scheduler/DEBUG: Looking for jobs to run
2025-12-24 00:17:24,224 apscheduler.scheduler/WARNING: Execution of job "job (trigger: interval[0:00:02], next run at: 2025-12-24 00:17:24 EST)" skipped: maximum number of running instances reached (1)
2025-12-24 00:17:24,225 apscheduler.scheduler/DEBUG: Next wakeup is due at 2025-12-24 00:17:26.222133-05:00 (in 1.996511 seconds)
2025-12-24 00:17:25,241 root/INFO: job end

With misfire_grace_time=None, I'm expecting the job to start every 3 seconds, but instead it starts at intervals of 4 seconds. "job start" is always on even seconds, when it should alternate between even and odd.

I did see a proposed workaround here, but this feels like a bit of a hack and something that should be in the domain of the scheduler.

Source: agronholm/apscheduler

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