I had this same thing happen when I first started, paired about 30 devices and the last devices I tried pairing was the zwave locks.......well everyone knows the troubles there. Apparently with the mulitple repeated attempts to actually get these paired, it locked up the zwave radio completely and all the devices go missing.
In my case while waiting on support I went through force removing devices and repairing all over, only to be told by Bobby to do this shutdown power cycle, at which I was skeptical because I too had done multiple "reboots"
Low and behold Bobby was right when the hub restarted all the devices were back (minus the ones I force removed)
