Your manager's boss shouldn't have given you criticism without your manager being there. You and your manager are the most informed about your work and it should have been a discussion among the three of you.

I think you're going to get more of the same. If not directly from your manager's boss, it will be passed down to you. And again you will be puzzled. It won't quite add up and will feel like you and your bosses are on a different page.

I would make sure to stay at least a year, then find something else.