Polyline in ImmediateMode gets updated even if not changed

Using the polyline example from the documentation in immediate mode generates a new mesh every frame. Even if I reuse the polyline object.

I "fixed" it by adding a meshDirty check in PolylinePath.TryUpdateMesh()

void TryUpdateMesh( bool closed, PolylineJoins joins ) {
    lastUsedClosed = closed;
    lastUsedJoins = joins;
    // todo: be smarter about this, maybe don't mesh.clear but check point count and whatnot
    if(meshDirty) {
        ShapesMeshGen.GenPolylineMesh( base.mesh, path, closed, joins, flattenZ: false, useColors: true );
    }
    meshDirty = false;
}

Did I missed something?