Dynamic Matrix - Selection from Slicers

Hello everyone, I need some help from the community.

I have a data model and I need to create a dynamic field in my matrix to bring the total number of records, based on the selection from my slicers.

What I have is this:
3 slicers with attrib. 1, attrib. 2 and attrib. 3.

1 matrix with a dynamic filter (I created a measure for this that you can see below) and the total of records.

PS: You can also find the pbix at the end of the post. 

My measure:

What happens is that this works very well if I have only a single selection in each slicer.
For example, if I select:
Attrib.1 = A1_Val2
Attrib.2 = A2_Val3
Attrib.3 = A3_Val1
This is my result and it's correct:

The problem I'm facing happens when I select more than 1 item in my slicers.
For example, if I select:
Attrib.1 = A1_Val2
Attrib.2 = A2_Val3
Attrib.3 = A3_Val1 and A3_Val3
This is the result I get, my selection for Attrib.3 disappears:

And I would like in this case my output to be this:

Since the data in my table is this:

Could someone help me with this?

This is the link to the PBIX file:
Sample_DynamicField.pbix

I appreciate the help from everyone in advance.