Ay, I haven't tried the new Bonna formula myself, pero a few of my mum friends actually switched to it at may slight bubbling din sila initially, lalo na kung hindi pa-adjust ang baby sa new formula, minsan talaga may transition period talaga. Try mo muna mag-mix ng old and new formula habang nag-adjust ang baby, or check yung water temperature at mixing method kasi sometimes yun ang culprit ng bubbles, hindi lang yung formula mismo.