This has been my experience also, with a Coti. The edge was shave ready (sharp and smooth) and when I tried to advance the edge with a slight slurry (just experimenting) the edge degraded noticeably. Why? I assumed it was the slurry but I can't say for sure. I then went to clear water and the edge came back to shave ready. My expereince with jnats is also nill so I can't speak to that at all.