Walk Behind Lawn Mowers

Having problems with my HU775K walk behind mower. I have a combination of Bermuda St. Augustine grass and no matter what height I cut it is pulling the runners out after the cut from my St. Augustine grass. I think the rear rubber safety protector is the problem. It appears to be mounted below the level of the cutting deck and is catching runners below the cutting level. Is this a problem for anyone else as this is a design issue and we should get a exchange or our money back.