Multiple attribute mapping to an object

I am not following this, Cameron.  Could you go through the situation again, perhaps with screen shots?

Hi Karl, 

See image below: 
When the user is trying to filter by username in the image below it turns red

Per L2: Its a product limitation. At any given point of time, an attribute can be mapped to only one object (in this case its mapped to User object).

Does this help?

I am sorry but I still don't understand.  What attribute of what object are you trying to map to which two objects?  

I will start from the beginning, sorry for not being clear originally. I should have included more information.

We sent L2 the following as the issue:
"When we try to set the filters in the report in the dashboard, we've found that while trying to filter by User Name, User ID, or Email, we are unable to use the "=" operator in the filter.
We can use a "starts with" and "contains" operator and it works just fine, but if we use "=", then we get an error for like one second and then it just shuts down the window.
A perfect example is to filter "User Name = (insert name)" and it will throw an error."

It was then accepted as a bug, after L2/Eng looked into they said:
 "Its a product limitation. At any given point of time, an attribute can be mapped to only one object (in this case its mapped to User object). So an attribute with such a mapping is . selected in the filter, autosuggest is enabled and the values entered in the filter are searched against the mapped object. If a contact name is entered, this means No Data would be found. This is the product limitation."