I poked around in your model via both the normal inspector windows and using Ruby via the Ruby Console. I found some strange things in the materials. I don’t know how they came about or for sure whether they are causing issues, but they seem to have the potential at least for causing confusion. There may also be some bugs in SketchUp’s handling of materials that add to the confusion!
There are a couple of kinds of duplication in the model’s materials collection that perhaps shouldn’t be possible but are there. There are multiple instances of identical colors captured by distinct materials. For example, “white” and “FFFFFF” are different materials that both have the same color. There are also distinct materials with the same name and color, e.g. two versions each of CristalGris, CristalAzul, and CristalVerde. There are distinct materials that seem to be some sort of auto-generated duplicate colors with new names, e.g. CristalGris1 and CristalAzul1 (I have no clue why there isn’t a CristalVerde1).
The Materials window for “Colors in Model” shows 14 user materials plus the default. The Model Info statistics window says there are 17 materials in the model (it never counts the default). Probing via Ruby I also found 17 user-defined materials in the model, of which 4 are not used by any entity in the model (the duplicates of CristalGris and CristalAzul and their renamed variants CristalGris1 and CristalAzul1). These are the 4 that are eliminated if you purge the model.
Turning to your Paleta_Swatch component, I found some oddities in how you have applied materials to it that might produce different results in the DC than you expected. You have put different materials on the front and back of three of the faces in the swatch, and left the front of three of the faces default while painting the back with colors. In the images below I changed the default front color to a shade of tan to make it distinct from the white material), I also labeled the top the faces 1-6 for reference below:
Top of swatch:
Bottom of swatch:
The materials applied to these faces are (front / back):
1 CristalAzul / Material4
2 CristalVerde / Material6
3 CristalGris / Material10
4 default / white
5 default / Material2
6 default / Material3
Those assignments might not do what you expected. For example, none of the 4 materials that get purged are used there and in three cases the front is defaulted.
I hope this analysis helps you sort out what you need to do (I am not an expert on DCs so I won’t pretend that I know what to do with your programming).