Past collaborator submitted paper with my name (and others) without notifying named co-authors
Person A is not acting ethically by submitting a paper with multiple names on it, but without asking those people to assess the paper and agree to publish it. In normal circumstances, you'd expect person A to discuss with persons B and C as well as you. I think that it is beyond doubt that this person is in the wrong.
However, it is unclear to me what is to be done about the situation as it is. Mainly, my question to you would be: do you support the claims made in the submitted paper? If so, it might be socially prudent to just accept that the paper was submitted as is. After all, science is a social construct, and we get nowhere without our network. However, if person A submits a paper where you don't support the main conclusions and puts your name on it, that would be a reason to vigorously oppose what is happening here.