You're referring to the Inbox app and not the Gmail app, right? I use gmail, so I can't say. Gmail's still notifying me on the watch. Sometimes all you need to do is restart it, but it seems like I've only had an issue when NO apps were sending notifications to the watch.My Google's Inbox email app stopped sending the notifications to my watch after the update. I'm I the only one?
You also might check in the AW app on your phone to make sure you didn't accidentally block the app from notifying you on the watch.