Duplicate Page Content and Missing Meta Descriptions Errors Appear Overnight

Hi all,

I handle SEO for several websites, and suddenly, the Moz Error Report for one of my WordPress sites saw an abnormal amount of increase in errors overnight, particularly Duplicate Page Content errors and Missing Meta Description errors.

I discovered most of these errors were due to two different tags being assigned to same post without any other posts assigned to either tag. Therefore, WordPress was creating a two tag archive URLs for the same post.

But the individual managing the content has been doing this for a while. I am just trying to figure out what made the errors appear overnight, wondering if WordPress changed the way they did tag archives. I also am not sure why all of a sudden the missing meta descriptions for the category pages and tag pages are appearing.

Any insight would be helpful. Thanks!