Thanks for the added details Brian.
I'm not seeing a 35% decrease. Or at least it's not obvious to me.
Regarding the reviews...
Google knows you manage those accounts AND left the reviews based on your IP.
Does not really matter to the algo if you were really a customer too. The algo paints with a broad brush and since MANY SEOs leave fake reviews for customers, you were put in that basket.
FYI THOUGH - I wrote a review for my vet. NO marketing relationship at all. Totally legit.
It never went live so I asked Google management why it was filtered. I was told in short, if you want reviews to stick you should use a Google account that is not tied in anyway to SEO. (Because so many SEOs write fake reviews for clients or do rep mgmt.)
So I'm not so sure there is a penalty here. And if there is it COULD be more about the fact that now having a bunch of unrelated businesses in one account gets penalized. (I'm not sure, just guessing.)
But as far as how long penalties last, I've seen them clear up 2 days to 2 weeks after the violation was fixed. BUT I've also seen penalties that lasted for 8 months.