Definately not immune to this issue myself. There are many variables that may contribute to shooting a periodic stray left.
A relaxed shot execution has been personally valueble in reducing errant arrows. And if one occurrs, I normally can discern what happened.
A routine that that works for me:
Start with a relaxed stance, bow hand and string hand and relaxed draw.
1. Relax at anchor with back muscles doing the actual work.
2. Focus on the spot, trust your bow arm and pause(for me ~2 seconds) while on target, slightly increase back tension and forward pressure in a controlled manner.
3. Release in a relaxed manner allowing you bow arm to move naturally forward then slightly down to the left. Allow your string hand to naturally move back as the shoulder blades move together.
The release and follow thru, if fluid, makes keeping my head down and remaining focused on the target much easier.
The smooth release thru a fluid conclusion is a great experience.