Raspy during bottle feeding

JKMM
Does anyone else have a baby who sounds raspy during a bottle feeding? My LO will be 6 weeks in 2 days, and is formula fed. At some feedings, he sounds raspy, almost as if he's trying to breathe through his mouth and suck from the bottle at the same time. It makes certain feedings take a long time and very difficult because we have to stop and take breaks a lot. He is not congested otherwise, and does not have breathing issues. Obviously I would call his pediatrician or go to ER if there was a concern. Anyone have any experience with this or know if it's normal?