The problem is due to the fact that when you make selections on a calculated field, such as in your listboxes, then the selection is actually being applied to the underlying physical fields. So a selection in listbox 1 as really making a selection on Email_Name. This is reflected as a current selection in listbox 2 as it has the same underlying field(s).
The workaround is that you need to modify the load script to derive these values as physical fields. This needs to be done at a suitable level of granularity so that your users can still make selections.
Logic will get you from a to b. Imagination will take you everywhere. - A Einstein
In this dashboard the expressions are based on the 'Consumer_ID'. Hence, aggregation in the script is not really possible.
Based on your explanation it would mean that i can also create a second dimension field, which is bascially is a duplicate (Email_Name and Email_Name1). However, that I think is not the nicest solution.