I had an incident last year where I moved an idle device (controlling a fan; not much used in winter) downstairs (to control the Christmas tree). I then lost access to devices in my stairwell. After wrestling with it for a bit, I had the idea that perhaps the moved device had been the node in the mesh that was getting from the hub to the stairwell. That turned out to be the case -- I moved it back upstairs and picked a different smart switch to run the Christmas tree, and all was well except that switch had a slightly more important job in its original location.
It would be really nice if Hubitat could map out which devices are being used to relay messages to which other devices, so we could pre-identify and/or troubleshoot situations like this more easily.