Is it near the hub or a repeater that supports beaming? If it is far away or not solidly in the mesh network you might have communication problems and thus the radios are constantly trying to get in touch with the hub.
I have similar situation going on in my garage - I just have not installed enough other devices out there yet to make the mesh solid enough for the wave commands to get out there. The lock on my back door has no issues because the mesh is stronger. The batteries in my garage also drain faster (but last longer then 2 weeks!).
Here is an FAQ from the always helpful @JDRoberts: