if you have beautiful flight of arrow...form is good...then the only thing left is whether you bow is centershot and whether you are either torquing bow or got too much face into anchor hand...if right handed all will cause left arrow impact.
is bow centershot...if not then it is naturally going to shoot left especially with slightly stiff arrow...have you bare shafted?
if everything is great as you say...may just be you need to get used to the bow and keep aiming the same and let your brain make the adjustments....
hard to tell with the info you posted...as it says nothing specific that would help:
-bow centershot, if not how far short or past is it
-right handed or left handed
-right eye or left eye dominant
-bow weight at what distance
-actual measured draw for you...not what you think it is based on other bows but someone else measuring your average draw while shooting with your natural form.
-arrow spine or deflection and how you came up with it (length of arrow, arrow point, fletching)
-b50, fast flight, etc for strings
-recurve, longbow (straight limbed, slight reflex, R/D) or selfbow
-locked bow arm, slightly bent bow arm, dropping bow arm at shot, torquing handle from tight grip?
-three fingers under, split draw, corner of mouth, under eye, floating anchor, etc....do you turn your face towards anchor point of hand or bring hand into face tight?
-how much have you shot bow just aiming for spot and letting brain compensate?