That didn't fix it.

In the manual under terrain_chunk it says this:

For avoiding unchunked mesh stripes, terrain_chunk should be a multiple of 8, and the number of terrain mesh squares in x and y direction should be a multiple of the terrain_chunk value.

Anyway, wish that would have worked. Might still be something like that, but 257x257 terrain didn't work.

To me it almost seems like the last vertex of the terrain chunk isn't being passed into the vertex shader part of the terrain shader. Which sounds simlar to what you suggested, but unfortunately that didn't work.

Thanks,
Loco