Yeah it happens. I hear that it is normal with the A-Bomb dose. It happened to me with the QHCocaine dose. So dont worry about it. As long as it does not persist into the following days or anything weird like that.
Yes, twitching is normal. Mostly happened to me about when i was starting dosing, but now i dont twitch as much. About the A-Bomb, i dont know, i am mostly "hooked" on the Opium one...