Here’s why that is happening. Look at the filter condition in the measure that calculates the score based on Slicer 2:
Assume Eddie is selected in Slicer 2, but not in Slicer 1. Since Slicer 1 is tied to Sheet1[Name], Eddie is no longer present in the filtered version of that column, and the filter condition above cannot be true, so it returns a table with no records, thus causing the measure to evaluate as blank, and the teal bar on the graph to disappear.
So, how to fix this? The fascinating (and occasionally maddening) thing about Power BI is that there are many different ways to do the same thing. This problem can be solved in a number of different ways, but the simplest is probably just to remove the filter on Sheet1 coming from Slicer 1 in our measure above by adding ALL in the table parameter of the FILTER function:
So now, the bar for Eddie shows up unchanged, regardless of whether or not he is selected in Slicer 1.
Hope this is helpful. Full solution file posted below.