Whether on my iPhone, iPad, or Mac, I very often get Due notifications on tasks that have already been marked complete.
For example, a task is assigned due by 3:00 PM and if not, I receive a notification pop-up; however, the task is marked complete at 2:15 PM, yet at 3:00, the notification comes up that it is due.
This definitely occurs if the device's GoodTask has not been opened recently to sync on tasks status; however, background push sync should negate any requirement for the app being open to properly update status.
Hi @pairof9s , thanks for the feedback.
As you described, if a task is completed in other device or other app, the app might still hold its notification. Background app refresh needs to be ran to get the notification cleared if the app is not opened before then.
Background app refresh is handled by iOS so there's not much I can do for that. On the user side, you need to have it turned on ind default Settings app and you should not force quit (swipe up on app switcher) the app to get it running.
The app tries to run it often and sends info from other device to wake it up but there are some limits as mentioned above. Check the ones you can do above. I'll keep an eye on it and will try to improve it when possible. Thanks!
That's understandable that GoodTask is dependent on the iOS sync limitations. Perhaps iOS 27 will provide improvements in this area.
Yes, I have both GoodTask and Reminders background app refresh active, and eventually, the sync will come through. But for example, even when I check off a task in Reminders app, it does not show as done in GoodTask for quite some time (30 min); the reverse (GoodTask > Reminders) seems to happen much quicker.
This is a minor annoyance, so I'll just keep GT updated to see if/when this improves. Thanks
Reminders app gets more privilege since it's their own app. 
I recommend running actions within GoodTask to get it work better. I'll keep improving it. Thanks!