When you say "pinch" I think you mean the workpiece moves toward and away from the fence a bit? Or do you have an "ear" sticking out on the last 1/2" that goes thru?

The fromer is cured by cutting the first cuts off a large sheet 1/4"+ oversize then flipping the fence edge to be the cut edge and trimming to final length witht eh more manageable=sized piece.

The latter is caused by the weight of the large off'cut falling away from the blade as you flinch a bit on the push through. When you get to the last few inches of the cut be sure and have a hand on each side of the blade pushing on the workpiece side and just following thru on the off-cut side. Despite the large size of either don't push just on the workpiece side. The offcut will always fall away and tear away, leavcing that "ear".