Insidious mobile redirects / AMP content discrepancy
As with the other penalty for "sneaky redirects," Google doesn't like it when webmasters show different content to mobile users than to desktop users.
Even more so if the mobile pages you want to get indexed and ranked well are optimized as AMP.
This manual action may result in partial or complete deindexing.
How to remove the penalty
Google wants you to show users the same content (albeit in different formats, designs, chinese overseas british database and resolutions), so make sure you audit all of your pages to achieve just that.
Pay particular attention to AMP content and its markup.
A Link Penalty Story: How I Removed a Client's Google Penalty by Cleaning Up Their Links
In 2014, I worked as a content writer and social media manager for a client in India.
Because I also offered SEO help as a professional "add-on" to our contract, my client came to me every time something in his SEO strategy didn't look right.
One day, this client urgently emailed me to inform me that Google had penalized his website for unnatural inbound links.
Since the website we were working on was fairly new, I asked him if he had purchased link packages from a link seller.
He admitted that yes, he and his business partner had bought dozens of backlinks from a guy who was selling them in packages for little money (probably from Fiverr or a similar service), assuming that with these new link signals they would quickly rise in the SERPs.