Sense is currently only supported on SuperPods or SuperPods with WiFi 6, so if the room only has another type of pod, you will not necessarily get Sense coverage in there.
Since each SuperPod will only use up to 3 Wi-Fi connected devices at a time, it is also possible that there are no devices near or in that room being used to detect motion, which is why there is no motion coverage. You can choose which devices are used for Sense by following the instructions here.
We recommend assigning devices to a room through the HomePass app to improve the personalization and accuracy of motion alerts.