No, this is not new, Google has been sending out these "note from your reviewer" notifications since 2014. But they are rare and maybe, just maybe, Google will be doing more of these in the future. Kristine Schachinger recently received one before the New Year and it was very specific on what the site owner must do.
Kristine posted this note on Twitter and it read "we recommend adding the rel sponsored or rel nofollow attribute (http://support.google.com/webmasters/answer/96569?hl=en) to links like "Android data recovery" in https://www.XXX.html"
Here is the screen shot she posted:
Here is one from Marie Haynes when I asked her about them, this is from years ago she said:
The note from your reviewer is not new...started in 2014 or so. But most do not get any note. This one seems very specific...hopefully that's the standard now.
— Marie Haynes (@Marie_Haynes) December 31, 2020
Here's one we had a few years ago. pic.twitter.com/7dskqCPZXA
I do hope Google can offer more and more details if a reconsideration request is denied but I guess it depends on the situation.
I should note, that help document link in the reviewers note redirects now to the new Google developer document section.
Forum discussion at Twitter.
