CC Poor Cut

I have a CC 2165 with a LT 300, 46", 3 blade, model mower deck. The mower is leaving what I call a "tuft" or 3-5" wide line of half cut grass towards the discharge side. On turns I get a thin uncut strip of grass. Have new blades, new belts, deck adjusted for height. The spindles are "tight" as there is not any wobble and spin well, no rough turning. Even replaced the discharge spindle side bearings, no change. Sometimes the opposite side looks the same.
Out of options, any suggestions on where to look or what to do?
Thanks, JC

Scrape the underneath of the deck clean of clippings. Make sure discharge whole is as big as it should be.