To me, the 2 extra grains of the same powder , with the same Bullet , same Barrel ,would produce a much higher barrel pressure & would cycle the action with much more force with the higher gas signature . Saying that , it is possible that the larger charge of Powder in the case , could actually lower chamber & barrel pressure ( before the Gas Port ) , because more powder is burnt ( or unburnt ) farther down the barrel . Different cartridge case volumes & Bullet diameter's can produce some odd characteristics .
I would try different power (s ) , magnum Primer maybe , if possible , I know nothing of this Caliber , so I have no experience with Powder choices .
Is the recoil more stout with the ammo & its extra Powder charge ?
Making the Port larger would be last thing I would do , because you can't go back , not that the end result wouldn't need it done .