Why is there a disconnect between the workspace "show details" field control name and the reports/custom fields column names?
It is standard functionality to display a control in the workspace with a capitalized start of each word. Additionally the spelling may be different.
For example, a field like answers.assgn_acct_id shows up as Answer.Assigned looking at it through Show Details in the ribbon.
All field controls are set up this way. You are not looking at the field when looking at the workspace. You are looking at the field control which represents the field.
For information on field names for report building, refer to the Data Dictionary.