You can probably blame the behavior on the hormones.
I'm not on T, but I take Mexican Sarsaparilla, which gives a natural boost to your own testosterone. I have plenty of my own, as a partial transmale.
It only takes a tiny amount of sarsaparilla to work, but when I first started taking it, I took too much. That's when I experienced a sort of natural plant hormone "roid rage," where I found I suddenly had a confrontational hair-trigger temper and felt irritable. Luckily, I resemble a tiny, delicate female, or I could have gotten fired from my job, or in a fight.
It scared me, and when I later began reading transmale autobiographies, I found that transmales starting on T often act explosively angry or become less considerate with their girlfriends, often resulting in a breakup.
I've read about transwomen acting out on hormones as well, and experienced the receiving end of moody craziness from an old high school friend when she started transitioning.