ts.StatusFlags sends 0 after headset stationary

Hey guys,

As part of our development here we are using the touch controllers to identify locations of physical objects in space (to be followed by the appropriate corrections to match physical to virtual). Tracking data is continuously being sent via: 

ovrTrackingState ts = ovr_GetTrackingState(session, ovr_GetTimeInSeconds(), ovrTrue);
if (ts.StatusFlags & (ovrStatus_OrientationTracked | ovrStatus_PositionTracked)) 
{
    ovrPosef pose = ts.HeadPose.ThePose;
    ...
}

Typically, we leave the headset lying around as we run the initial "localisation" session. Unfortunately, after a while ts.StatusFlags goes to 0 and the positions of the touchh controllers don't change anymore until the headset is nudged. Is there a way around this? A different flag to ts.StatusFlags for controllers too? Should we remove this entirely?

Many thanks,
Joey