My T does this a lot, if something is relevant to my issues or the topic we're discussing. Never many details though, just "I have a client who does (x)" or "Many of my clients also deal with this".
It did bother me at first (I know she doesn't name them or anything, but still, what about confidentiality?), but then I just accepted it as part of her MO.

Recently though I've gotten a bit mad at my T for several reasons and I'm starting to doubt her abilities a little, so maybe this just further shows that she's not that good at her job.

(She also self-discloses a lot... sometimes too much, I think. I mean, I didn't really need to know when she lost her virginity... )