Hi
Has the knife face ever been on the stone flat?
as said above, convexing it may work. Try sharpening it on sand paper with soft backing.. say either soft leather or say 20 paper of newspaper or what ever is required. IN addition, leaving the striations from 600 grit sandpaper will leave fine serrations which may reduce stiction if you had smoothened/ polished the blade face before.
a) Thinning it at a very low angle with starting grit of 400- 600 auto sand paper and then higher shld you desire a smoother finish.
b)The final edge can still be on sandpaper , finer if you prefer.
Question. : are all lasers being thin, really flat at the blade face? Is it a fact or supposition?
Have fun.. rgds
D