There's a lot of difference between shooting groups where the group itself falls to the left of the bullseye, and occasional (or maybe more than occasional) shots that fall to the left of the bullseye. Guessing that it is the later case, the cause is probably inconsistent form. Find Terry's clock on this forum. Look at the shoulder. If your shoulder is lined up to the left of the target, which it would be if you're shooting from an open stance and not correcting for it by pivoting your shoulders square to the target, then the tendency is to shoot to the left. This can be corrected by either pivoting so your shoulders are square to the target (easier), or by leaving your shoulders parallel to your feet and focusing on pushing toward the target (harder). This is one of about a dozen things that could cause this problem, but is probably the most common.
I just reread my post, and don't mean to imply that you don't need to push with the bow arm toward the target if your shoulders are square to the target; it's always necessary to push with your bow arm toward the target. It's just more critical than ever if your shoulders are not square to the target