Stick Up Cam Battery detection problems

I have recently purchased 2 x Stick up cam battery version (3rd gen) and they work fine with detection inside the house. My problem is when I put the cam against a window looking outside that it will not detect motion.Can anyone tell me what is the max detect distance for these cams and why my cams will not detect through glass window ?I am getting a RSSI of -53 for one and -58 for the other device.I have them working off of the latest version 4 Virgin hub which improves wifi connections.Thanks for your help on this.Chris