I have a Buffalo that was doing the same , turned out that the bow took quite a bit less spine than what I was used to compared to my other bows of lesser wt.
My Hummingbird takes more spine than my Shrew Model T , both have the same poundage.
Also I shoot with glasses , I have to watch my head position or I end up looking more out the left lens. This hooks em hard left like magic.
Also make sure you aren't pulling into your body in any way. this also hooks em left.

Check out Terry's form clock threads.  It could be shoulder alignment?  No amount of tinkering will solve that. (except for maybe looking to the right of what you want to hit.. ala stabow)