Eufy smart doorlock S330

I have eufy Smart door lock door bell S330.

Sometime I notice that the lock is hard to manually open. most of the time it is normal, but sometime I noticed that I really have to force to open the lock.

THere is no issue opening from the app or from the fingerprint.
From inside manual open seems like it is hard sometime to open. and I am fear not to damage the motor or anything.

Is this normal? do I need to tweak anything in the settings?