Data doesn't show up in the calendar and grid view, but can be found through search. And the statistics area below the calendar shows the correct number rather than zero.
It's a bug related to DST(Daylight Savings Time). The code we used to query from the database for grid and calendar view is affected. All your data is SAFE, it's just hidden.
What to do?
Please stay tuned for the next update. We've been working around the clock to deliver it ASAP. Please don't try to uninstall the app, or you might be under the risk of losing data.
We are really sorry for the trouble with this. If you have any question, please contact us at https://griddiary.uservoice.com
[Update 2014.03.17] We've submitted an update to Apple.