Test flight update problem

I have three ATV’s all running test flight. Auto update is on for all of them yet I notice that they are not all updating the beta each day. The update seems random, one or two will update and the third doesn’t. Then the next day only one ATV will update. Some days none update even though I can see a new build is in the list. Any clue as to why the updates are so random or is there something I’m not doing?

Do they update while not in use or only when on? I have them all go to sleep when not in use, mainly to stop the Channels app and server from streaming when not actually watching tv.