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There are hundreds of webmasters complaining and worried that their structured data is messed up, because Google Webmaster Tools seems to have a bug where the reports show a massive decline in the number of structured data elements a site had compared to the previous day.
If you go to Google Webmaster Tools and view your structured data report, you and I both will see this massive drop. Here is a screen shot from this site:
I am not the only one with the issue, there are tons of reports of this issue. We have many threads at Google Webmaster Help and one at Moz (thanks Keri) and a bunch of reports on Twitter.
Like I always say with Google Webmaster Reports, they are delayed, often run into bugs and issues and will be cleared up probably soon. So do not worry, you are not the only one seeing this massive drop.
Forum discussion at Google Webmaster Help and Moz.
Update: Google's John Mueller said Google is investigating.
Update: This was fixed today.
