The barrel must be bent. Send it to me and I will scrap it for you!
Seriously, shoot the gun from a rest to eliminate the gun being the problem. Trigger management is the most troublesome fundamental of pistol shooting, followed by grip. I see this occur with right hand shooters in every class even with experienced shooters. Especially with Glocks for some reason.
If you extend your arm straight out and make a fist, you will notice a slight movement of your wrist to the left. It is body mechanics. Add to that your trigger finger putting left torque on the trigger, which pushes the muzzle a little to the left. Also, if you have too much trigger finger in the trigger guard where the fat part of your trigger finger is rubbing on the frame of the gun, you are pushing the gun to the left. That is why we teach students to use the center of the first pad of the trigger finger pad on the trigger. Shots go low because of shot anticipation. If you know exactly when the gun will fire you are going to react in anticipation of the shot.
These dynamics occur naturally when working the trigger of a handgun. It varies in degree due to differences in hand structure and differing ergonomics between guns. You can minimize and counteract the tendency by using a thumb forward grip with your support hand. Practice your grip and trigger management to develop neural memory to get a straight back trigger pull.
But then again, it could be a bent barrel...