Drill did not correctly preserve output field's case sensitivity

For the following query,

select EMPLOYEE_ID from cp.`employee.json` limit 2;
+-------------+
| employee_id |
+-------------+
| 1           |
| 2           |
+-------------+

Even though upper-case EMPLOYEE_ID matches the field 'employee_id' in the input JSON file, Drill did not preset the upper-case in the output result, which seems to be not right.

The plan coming out of optiq/calcite seems right, as it has a project which will do the renaming. But Drill's logical planning will remove such project, hence not being able to preserve the upper-case in the output.