Yes. Exactly right. On very hard, flat stones the edge will tend to stick when using plain water. This stickiness can stop movement of the razor across the stone and always impedes a smooth sharpening motion. Many sharpeners use this as a sign that the edge is as sharp as it can get, so they stop. I interpret it as an increase in friction as water is pushed away between the edge and the stone. This messes up my feel for the edge as I move the razor. A tiny amount of dish washing detergent [I used to use glycerin] solves this problem and lets me use sharpness testing to determine where to stop.