GYLF, you know that I think there is a good chance you may have a form of AIS. It can be that estradiol for you is like nitro in a dragster.
I have related before that I had gynecomastia since I was a young teen. When I was one HRT - a blocker and low dose of 17-beta extradiol in patches, my boobs exploded during those six months. Since I had to go off hrt, they receded somewhat, but the glandular tissue has remained. And it continues to slowly increase. It is sort of like the switch did not turn off all the way.
I am happy with that, though I think I would really like to get on to a full transitional dosage. No such luck for now.