I make my tips round, if one doesn't behave, I heat the tip, put it in a padded vise and turn the bow handle the direction I want the tip to go, just little tweaks, let cool and restring to see if the string tracks perfectly in the groove. I usually have to do this with all of my tiny tip recurved bows.
This is a recurve tip I had to tweak to get it lined up correctly, it has a round cross section on the belly.