lots of people have actually experienced this effect of shortening while on hrt, most drastic are people that are at a younger age,
i believe that the change in height is due to one of the effects that is already known about hrt, a reduction in cartilage all over the body, this is most likely the greatest factors in change in height,
every joint in our body is coated with cartilage, and when there is an increase in wear on them (increased muscular tension), or in males a higher testosterone level, these cartilage increase in thickness to reduce shock and prevent wearing out.
now if every joint in your body that had an effect on your height had its cartilage reduced by only 1/32th of an inch how much height could you potentially lose, greatly reducing your height in your torso area due to the number of joints in your vertebrae.
any conflicting medical insight into my assumptions would be much appreciated