Layered Pivot Table Has Blanks

I have a big dataset with around 100k lines and I'm trying to have a chart that display information regarding question ratings.

So I have skill ID 1-55, each question has a rating of 1-5.

When I stack the skill ID (in the picture below) 1-4 for the rows and the values I stack the counts of skill ID 1-4 it has these like (blank) (blank) (blank) sub categories that represent the next question.

I want to display a chart that has a slicer so that they can select the skill ID and see the total times a rating of 1-5 was selected for that specific skill ID.

If I collapse the blank, it won't show the counts of ratings 1-5 for the filtered skill ID.

How do I fix this or does it have something to do with my data?

Do you have blank values in the rating field?