Gravel Filter Bug

Hello there! 

I am having some problems with the Gravel Filter when using a custom mask. The areas where I paint affect the Roughness, Height and AO, giving a full black render. Here you have an example: 

Here we can see that it has crushed the height information with a black color (the same happens in the ambient AO and Roughness).

For the rest of channels seems that there is no modification (The image avobe gives the example of the Base Color map).

Best regards,

Francesc Loyo