Power KPI Matrix 3.1.1

Hi all, I'm having problems when adding categories to the matrix in a column-based scenario. 

All works fine, I have 2 metrics that are shown well. The problem appears me when I try to add Category and Sub-Category in the matrix. This is the process that I follow:

1. The 2 metrics show well in the matrix

2. I add "Metric Name" in the category field. Nothing happens, but it's normal. 

3. The problem raises when I add "Sub-Category" after "Metric Name" in the category field from Metric table. The new sub-category column appears but then 1 metric dissapears from the matrix

4. Then I add "Category" after "Sub-Category" in the category field, new column appears but matrix shows nothing, it only shows the headers. 

I checked the data, matrix properties and a lot of stuff but I don't found the solution. I reviewed the Matrix Sample which is working but I cannot find differences versus my matrix. I realize it must be a problem with my data or something else in my report but I can fix the issue. Any idea? I'm sure it must be something I'm doing bad, but I'm stucked. Any help is apprecied. 

Thanks in advance, 

Abel