I've had the same thing happen. When I first start shooting, I hit low left. Then, I remove the magazine and do a dry fire and I am amazed at what I do. Due to the long trigger pull, once I have it pulled back about 3/4 of the way, I start anticipating the recoil of the gun and begin putting more pressure on my grip. When I do this, I "push" the back of the gun up and with my left hand pushing as well, it goes to the right slightly. This results in the barrel going low left. This is purely because of the trigger pull, for me. I am used to the short pull of a Glock and an older S&W 9mm, since that is what I have shot before, that I have developed this set sense of the exact pressure to apply to have a shot fire. Then going to a trigger that is 9# or 8# or what-have-you, that muscle memory that I developed ends up hindering my shot of a different gun. I've tried to correct myself but those first couple shots are always way off. Instead of trying to relearn to how shoot, essentially, I have decided to just buy the Apex Tech spring kit and make the trigger pull be about the same as my previous firearms.
Another thing to keep in mind is you have a cold barrel when you first fire. The most difficult shot a sniper has at any range is the first bullet to leave his rifle because it is the least accurate. A warm barrel causes the rifling to act more efficiently. With a barrel as short as a pistol, the shot is already less accurate than a rifle, so one would assume that "shooting cold" would have much more of an effect on the trajectory of a round than it would on a rifle. Just something to keep in mind. There is a reason people "warm up" before doing any type of competitive sport.