Polynomial Issue with User-defined Variables

I have a 2D rectangular geometry that has porosity and permeability values dependent on x-coordinate. Polynomial expressions are used to define the local porosity and permeability. However, COMSOL does not accept a variable expression such as (x^2+x) because it tries to determine units and cannot add m^2 to m. Is there a way to use polynomial expressions and get around this units issue?

File is attached. Variables are defined under model definitions.

Thanks

Burns