Using Oculus Rift, when you press the menu button ( called Button.Start) to get to SteamVR menu, and come back, the glove/hand models cannot be seen, not from the HDM and not from the editor.
Sames happens if you take off the HDM and put on.
before:

after:

To test it, all you need to do is put the player prefab on a new scene, and run the game. open and close steamvr menu and it would happen.