Terrain collider displaced?

A rather strange thing happens to my terrain. For some reason, after rearranging some assets and restarting my computer and Unity, all objects sink about 5 centimeters into the terrain. Everything works fine, but objects just sink in a bit, like the terrain collider is displaced form the renderer.

Any ideas as to what might cause this?

Also my terrain often costs about 400 draw calls, which seems very high.