I have given T and Pdoc full permission to discuss anything (if they were in a clinic setting this would be quite normal). I don’t think they have ever talked but I don’t care if they do.
If their talking brings up so much discomfort for you it makes me wonder if there is a lack of trust in one or both of them. IMO why it is so upsetting that they shared this information might get you farther than focusing on them having shared the information.