Schlage lock not consistently disarming the alarm

Most of the time, users put in their lock code and it disarms the alarm. Occasionally, it does not. I'm trying to figure out why (I called Ring support and was told that this functionality doesn't even exist, so that was no help).  The way this is supposed to work is that the user puts their code into the lock and the alarm disarms at the same time. Usually, that works just fine. Once every two weeks or so, instead of getting the unlock event linked to the user code, it just says "unlocked." When that happens, the front door sensor goes into entry delay and the user has to enter their code at the alarm keypad. Since they aren't used to doing this, they inevitably panic and do it wrong and the alarm goes off and the cops get called before I'm alerted if I'm not near my phone. I'm trying to figure out why this happens and if there's anything to do about it. There's a range extender about 4 feet from the door. Is that the right placement? Do I need another one closer to the base station? Base station is down one flight and about 20 feet to the left of the door/keypad.