Sounds reasonable. If you're using REPEAT texture access you're set up for surprises. Real thing is, you don't assemble chunks to make a big terrain. We slice big terrains into chunks instead. All bounduary samples must use inter-chunk fetch. Seamless chunks hide the problem at an extreme authoring cost and limitation, don't do that.
I was thinking maybe it's because my normals are being interpolated when sampling the chunk normal map in the pixel shader?
I already use neighbour chunk vertices for border cases if that's what you mean
Is this seam there if you just go by normals, no normal maps?
What do your texture coordinates look like?
(Your normal map isn't in a texture atlas, is it?)
Yes, i just tested and the normals look fine when passed with the vertex. I guess it is a problem with the texture sampling... Any idea how to fix it? Or rather, why not just pass the normals instead of using normal maps? Does bump mapping even work when the texture resolution is the same as the vertex resolution?
And no i'm not using an atlas; a separate texture per chunk
If you are using bezier patches, make sure you are joining your patches with at least C1 continuity.
I don't even know what that means