The reason why BO and PM give permanent belly fat is because estrogen encourages soft jiggly subcutaneous fat storage. As opposed to the androgenic hard belly fat testosterone gives. This typically goes to the thighs butt and belly.
I actually don't mind the belly fat and am loving it. And Mines definitely gotten fatter, but also my inner thighs are really soft and jiggle now. And my ass just feels fuller and I can feel it jiggle when I walk.
Anything that's going to cause breast growth on a chemical level is going to make your body store fat in the female fat storage pattern if youe diets in a calorie excess.
And women store fat more easily than men so if you made no changes to your diet and started HRT or BO or PM then your already in a calorie excess.
I'm not sure permanent is an accurate description of said fat, but. Let's just say it's really hard to get rid of. Harder than most people have the will or energy to combat it. So practical purposes, permanent.