Doorbell not ringing properly

Ive had a few instances where someone has rang the doorbell butnit hasnt worked properly nor got a notification. Basically what happens is when you review the feed from the day you can see someone has tried ringing it. The initial default ring is muffled/garbled then the smart response kicks in. But i dont get notified on the app. Most of the time it works no problem, just happens occasionally. Anyone else experienced this??