I have rarely seen what was originally called the Google sandbox effect, have you?
Newish website (not too big, so not thousands of webpages) started to get good rankings (meaning some semi-competitive SERPs = decent traffic numbers, in the hundreds not tens of visitors a day) then wham, traffic drops to barely anything (under 50 visitors a day) and takes months before it starts climbing again.
That was the original description of the Google sandbox and many webmasters got hit with this traffic drop when this effect first came to light, but I’ve not seen this since.
Continue Reading When is a Google Penalty not a Google Penalty?