I recently picked up a couple motion sensors from eBay, as part of a lot. They are Xfinity XHS1-UE's. They paired up as Generic Zigbee Moisture Sensors. I changed them to the Generic Zigbee Motion Sensor device, and they work for about 30 minutes, then stop reporting. I get battery, motion, and temperature.
its unlikely that any of these 4 devices are helping this sensor stay in touch with the hub...
To verify that they are an issue (or not), unplug the four of them temporarily, pull the battery on the motion sensor, then see if that helps...