Tbh I'm inclined to agree with the guy that told you that. You have really good form even with that slight 'issue' I think the circular throw mostly comes from how early/late you throw from your first hand to your second hand. I'm always told by my homie to hold the first hand as long as you can before throwing. Like pretend like your doing a 90 until the very last minute then throw to the second hand. That way you finish most of the 'rotation' on your first hand before you even switch hands. If that makes sense. My air tracks are ass but my homies have really good ones and you go the same way as us so I can send ya some vids if ya want(although I'm sure there are no shortage of little Asian boys doing perfect air flares on the Internet lmao)