Yesterday, it seems Google has sent out a surge in "Incorrect Hreflang Implementation" notifications via the Google Search Console. The first time we saw this message was back in July 2015 and since, we haven't seen many - that is until yesterday.
Yesterday, the Google Webmaster Forums filled up with dozens and dozens of webmasters about this notification. I can't even link to them all. We even have tons of posts on Twitter including from @gfiorelli1, @richardbaxter and @Marie_Haynes amongst others.
Here is what they look like:
The thing is, many are saying the notification is wrong. But when questioned about it being wrong, Google's John Mueller said on Twitter that it is time to fix things.
@Marie_Haynes Time to fix things :).— John Mueller (@JohnMu) February 18, 2016
I asked John Mueller directly and he seems confident the notifications were sent correctly:
So I would check your Google Search Console message area to make sure you do not have any of these errors. It should only apply to international sites that deploy ahref lang.