I've never had actual gyno in the whole time I've been on HRT, but only recently on this last cycle of IGF and M1T, just last week in fact, I noticed that my nipples were just a little bit sore. To my surprise, I was able to get a tiny bit of fluid out of them but they are not puffy.
Considering that I was on a pretty long cycle of IGF (and it was still working when I came off although results were starting to decline), that probably contributed to it besides the M1T. (I heard that many users of M1T by itself also experienced fluid from their nipples but without the regular puffiness of gyno.) I have cycled M1T about three times prior already but never experienced any sore nipples or anything related to gyno so I have to conclude that the IGF made me more sensitive to it.