Cycles bake inverts a polygon on a normal map. A strange shadows with the normal map I get a flipped polygon after Cycles bake.


How to resolve it?


When I apply the normal map I get the strange, sharp shadow on the border between dark side and light side of the cylinder.


Is it bad baking or very low polygon mesh?

How to improve it?

Link to .blend file if necessary:
After recalculating normal on the lowpoly mesh (Ctrl+N), and shading it smooth rather than flat, I found only one small error remained, and it was caused by the light, not the map. so here is the re-baked normal map, but if you see a really sharp contrasting shadow, it's a different problem.