I had also got the same problem,
2014 Nove, moving from wp.com to self hosted, I keep on using jetpack on my selfhosted.
2015 Nove, migration to other hosting company, I keep on using jetpack, and I realized there are some error a week ago, Well actually i dont see any decrease in indexed / search page but i just think if there any way to reset this error… so it is clean on my google analytic dashboard.
Thanks in advance