Splining Rivers Creates Seams - Require Help

No amount of adjustments to the spline nodes or the MapMagic properties seems to fix this issue. Splines that adjust the terrain height in any way, or cross between tiles, create seams.

I am simply using a scatter node, interlink, pathfinder, relax, and stroke, then blending the result with the base terrain. The result is not seamless. Changing tile size/main margins does not solve the issue.

I normally do not go to forums like this, but the spline asset did cost $22.50, and there is a certain expectation that comes with that. Anybody else having this issue or have any ideas about how to fix it?