Erosion node causes seams, but only in play mode

When using the Erosion node, seams are caused in the landscape, even when using margins of 16. I've tried even margins up to 128 but erosion nodes don't merge terrains together.

Strangely, this does not occur in-editor when pinning terrain. It only happens in play mode when generating infinite terrain.

To Reproduce:

1. Start new project
2. Import Map Magic 2
3. Import the following bug demo package: https://www.dropbox.com/s/c3qyxf7bjx28voo/Map%20Magic%202%20-%20Erosion%20Seams%20BUG.unitypackage?dl=0
4. Enter the folder: "Map Magic 2 - Erosion Seams BUG"
5. Load the scene: "Map Magic 2 - Erosion Seams BUG - Demo Scene"
6. Hit "Play", the main camera is setup to display the bug.

In the same folder is the graph that causes the issue, it's very simple, only erosion node.