Auto lock not working when it is manually unlocked

This is now my second lock that has had problem after 2 months of use. First ones drained the batteries in under a week and just kept doing it. Returned for a new lock. Now every time I leave my home and manually unlock, I come home to an unlocked house. Seem to auto lock if I use the app. If we use our fingerprints or code, it auto lock 50% of the time. We are getting tired of always trying to trouble shoot the problems with this lock. And yes I have the latest firmware and I have removed the batteries and have also reset the lock. Autolock works one time and then stops working again.