Need help fixing a landscape texture. [Error]

I have been trying to make a landscape material texture, but whenever I put a landscapelayerblend and attach my textures, I get this error;

[SM5] (Node LandscapeLayerBlend) Arithmetic between types float3 and float4 are undefined

I got no idea how to fix this and I can’t seem to find anyone who has had the same problem, help please?