Had the same problem, what I found by trial and error was the Facebook beta app, after the last update to that app all of my tiles stopped updating, the way I found it was causing the problem was I thought about WHEN did the problem start and what apps I had download or updated from around that time, then removed each one, one by one checked if tiles started working, if not reinstalled said app and went to the next one until I found the one causing the problem, finally found it was the Facebook beta app, when I removed it tiles started working like they should, it was a pain in the rear of course, I suggest you think about WHEN they stopped and try to correlate to that time to any app updates since that time or new apps you might have installed