I think my T would never talk about clients so that I could recognize them (like e.g. talking about the client just before me). I only can see that she had a tough session from her face and expression but we don't discuss it. About other clients she said something only twice and it was very general, like that's good that I can tell her whenever I think she did something wrong because some clients cannot do even that etc. but nothing specific and for sure not venting - I guess it would be really weird for me, especially if I could recognize the client...