Had another original XT camera that motion detect stopped working. Knowing these cameras love restarts via taking batteries out for 30 seconds or so, then putting brand new batteries back in…I found a couple of new things.
New batteries always worked. Measure existing battery voltage - if 1.50 Vdc or higher, put back in the original batteries got the motion detect to work again.
Another way to get motion detect working was to delete the camera from mobile app. Then do the add new camera routine which is actually a reinstall of existing camera. You must know the serial # of the camera to do this however. After reinstall, you can change order display of cameras to your liking.
Does it work on XT2 series I don’t know as I don’t have any. My guess is yes it would work and the add camera is reinitializing the camera, thus resetting the motion detection to work again.
If you did not document your serial numbers of cameras during install, you should to it during battery change. The reasons for this are now obvious.