Is it possible that a site that has an average CTR of 10.5% over the past month suddenly have 0%? Does it sometimes take the clicks a while to catch up with the impressions?
I'm sure there are other people have may have more insight than myself but through my experience shows that the impressions and clicks are updated at the same time. Assuming you have not made any major changes to the layout of your site, if you have 0% CTR, I'd look at your log files. Try to find out where your traffic was coming from when you had 10.5% and when you had 0%. That would at least be a good place to start.