I'm having the exact same problem. Five minutes from the doorbell camera seeing someone/hearing a sound at the door, to the notification coming up on my Samsung Galaxy 10+ on the same network and while I am in the house. Even when someone rings the bell, there's a several second delay on the speaker notifications. This and other Google home delays and bugs are putting me right off the whole kit. why should I continue using stuff that just isn't working as it should?