shift one or 2 blades to one side. preferably one left and one right. doesn't take much.
Let me ask if this rough section is with a new board you are planing for the first time. It may be that the board has enough cupping in it that the knives are not reaching that part of the board. It commonly occurs when you are planing rough lumber. Just asking...and all of a sudden part of the wood isn't coming out smooth.
If they are indexed blades I am not sure you can shift them. I am thinking back to my DW734 that I had before I got a 15" Grizzly with a spiral cutterhead, and I don't think those could be shifted. There were holes that indexed the position of the blade. Maybe there was little lateral play in them, I can't be certain since I no longer have it.