[Django]-Celery beat process running on Heroku sends task twice

I had a similar issue. Not sure if this will work for you but I ended up removing the CELERYBEAT_SCHEDULE from my settings file and instead created a periodic task in my tasks.py file. Just decorate the function you want to run like so:

@periodic_task(run_every=timedelta(seconds=30))

I had mine run every 30 seconds, but you can change it to whatever interval you want.