I am having the exact same issue since moving my account over to Google. My Aria Air has stopped syncing. I have just contacted Google Support and they have created a ticket number, hopefully they can resolve my issue. However on searching it seems like this issue has been here for long with no resolution yet.
It might also be the case where people are migrating over from a different email to Google account. Like in my case my original account was via a Hotmail email and now since moving to Google it's on my Gmail. Was is it a similar case for you too? I believe this could be a basic email sync issue not handled well by the folks who built the account migration workflow.
