I will start with a picture (I know it's a bit difficult to see):

As you can see in the report I have three groups:
- Organization level 1 - with some grade and indicator
- Second group grouped by the entity type (person of organization) and each one has an average grade with indicator
- The third section is a list of persons of organization with their grades and indicators
The indicators are set follows:

The problem is that sometimes the indicator shows the color yellow when the grade is 100 (the indicator should show the color green).
I have checked the following:
- The grade that returns is 100 but the indicator still shows the color yellow
- I have tried to create c color expression and the result was the same.
I have started to think that this is a bug of Report builder 3 / Reporting services