Issue in selection variable screen

In one of our report in filter for business unit, when user is trying to change the Business unit in selection variable screen, he is getting only key for some of the Business unit in spite of both key and text initially. If we make Key/Text for Business unit, still we are getting Key, i.e. Technical name of that business unit. And no description.

Could anybody help me out and tell me the reason for the issue? If we want to make display both Text and Key, what need to be done at query level?

Thanks in Advance