This is probably due to whatever repeating device the ST motion sensor has chosen to route through. I rarely see an end device being a child device of the hub, generally they are always routing via a mains powered repeater. If they become a child device, they usually switch to another device as soon as the hub is rebooted, firmware updated, etc. You can download the Zigbee Map app from Hubitat Package Manager and see what device your sensor is routing through.
Mine is still sorting itself out after a UPS shutdown last night.