There are always extreme outliers in virtually any algorithm but when that outlier hits your site and your web site drops in the Google rankings, what do you do?
The answer is nothing, wait, maybe start a new site, maybe just give up.
Here is John Mueller talking about a specific outlier case, which he does not call a false positive in the algorithm, but something different that he can not share.
John said at 26 minutes and 55 seconds into the video:
It is a tricky case where I don’t have much liberty of saying much of what is happening. This is an an individual case and is pretty much a unique case. It is not really helpful for other webmasters. I know it is frustrating and I wish I had something more specific to share with you.
Watch John answer it:
I can't figure out if it is a problem with the site with algorithms or something spammy or something technical. Technical issues, he would be able to answer. So I am not sure.
Forum discussion at Google+.