Shading goes wrong with normal maps

Hello guys

I created texture for this object and it looks a bit okay, but when I add normal maps shadows become very weird. Why it happens and how it may be solved?

As you can see, borders of the regions with different shadows are borders of pieces of textures, so I believe that problem is somewhere there.


Found the solving
If u got the same trouble, read here

On the normal map - texture node.
Sorry for the capital letters. LOL.
I’m also not user how this normal map is baked.