hard to troubleshoot just from the network, but I suggest you put all displacements before the compute terrain node, not after it.
Lateral displacements can be very odd if the displacement is relatively extreme, I don't know if you have any of these.
The distribution shader's altitude and slope constraints before the compute terrain might work based on wrong texture and slope information, should you use these constraint up there.
Slope requires a computed normal, and altitude requires computed texture coordinates (tex coords from xyz).
Frank