LandMass River brush tool?

Hi all,

So I started using the Landmass plugins today, and I came across an interesting problem.

The Custom river brush only shows the water if the spline is running uphill. Now call me crazy, but I thought rivers ran downhill.

When you look under the map, in the inverted or sunken land, where the river should run, the water is just below the surface. I am guessing the offset between the brush and the water material is off, but having messed around with all manner of setting doesn’t seem to produce any measurable differences. I am using the Brushes default settings, so either the tool is bugged, or it was accidentally adjusted before being pushed live.

Does anyone know a fix for this?