Delayed intrusion and false intrusion alert

I purchased a ST monitoring kit during thanksgiving 2016 and the setup was a breeze… like it till now. I have 3 MP sensors, 2 motion sensort connected to the Hub. Then from the 1st night onwards I started getting incorrect intrusion alerts on 1 of the multipurpose sensors. And then within the same second or immediately after, the sensor declares the doors are closed. This is causing of confusion as to ST is the right tool for this monitoring job. I have read on other topics in the forum about the same issues and dont see any response from ST on this.

Second issue is that I was testing the sensor sensitivity and notification duration, I see that the notifications for intrusions sometimes come immediately and sometimes in a few minutes. So what is the point of a monitoring system that does not notify you instantly?