Shader Mixer - Operations on base color break metallicity.

Falco

In shader mixer using IRAY PBR Metallicity Base, if I do operations on textures that output to the base color, such as multiply 2 textures together or have a base color texture be masked by a LERP, while the material will render fine when Metallicity is set to 0, when Metallicty is set to 1 the material will render as bright white.  When i plug a texture into base color directly it works fine, but as soon as I multiply or lerp the texture the metallicity breaks again.  

How can I solve this issue and still be able to do operations on the base color while not breaking metallicity?