Error when masking refraction with a depth node

So I have some normal maps multiplied by a depth blend node going into the refraction slot which causes errors, it only happens when the depth node is used for refraction:


The errors:
Shader error in 'Shader Forge/Water': Shader program had errors at line 38

Shader error in 'Shader Forge/Water': Program 'frag', unable to find compatible overloaded function "saturate(error)" at line 139
Keywords: DIRECTIONAL, LIGHTMAP_OFF, DIRLIGHTMAP_OFF, SHADOWS_OFF

Shader error in 'Shader Forge/Water': Program 'frag', undefined variable "partZ" at line 139
Keywords: DIRECTIONAL, LIGHTMAP_OFF, DIRLIGHTMAP_OFF, SHADOWS_OFF

Shader error in 'Shader Forge/Water': Program 'frag', undefined variable "sceneZ" at line 139
Keywords: DIRECTIONAL, LIGHTMAP_OFF, DIRLIGHTMAP_OFF, SHADOWS_OFF