Not knowing what diagnosis you are talking about makes it a bit hard to know how to reply. If the diagnosis is not one in a therapist's normal realm of expertise, then she was probably right to leave the diagnosis to the experts in that particular area. Otherwise it is a bit like arm-chair quarterbacking. Sounds like it had crossed her mind but without having the expertise to make that kind of diagnosis she left it between you and your specialists to figure out. (Again, just a guess.)

Personally, I prefer it that people who really don't have any definite expertise in something keep things to themselves. My husband has a rare neurological pain disorder and when people start making suggestions, etc. based on absolutely no real knowledge of his condition but only on their gut and their arm-chair quarterbacking, it is annoying. The information they give is almost always incorrect. In fact, our T is really bad about doing that to him concerning his condition and it really causes a great deal of fall-out at home when my husband is unable to remember that T really hasn't the foggiest idea what he is talking about in terms of my husband's medical condition. (Note to self to remember to chew T out about this very thing next time I see him.)

Your T may have been very much doing the professional thing to keep her opinions out of it if she felt she really didn't know enough to make that kind of a diagnosis. Trust me. Be thankful for small favors.