A 2D DXF/DWG Export does not maintain the geometry's orientation to absolute.
Solution
There is currently no option to export geometry based on a selected coordinate system using the 2D option of the AutoCAD DXF/DWG Export Wizard.
In this particular case a custom view had been created where the X-Y plane of the absolute coordinate system was parallel to the screen and rotated about the Z axis by 45 degrees. The 2D option was selected and the custom view selected using the Data to Export step. The expectation was that the geometry would import based on the absolute, not the oriented position.
However, the command loads the selected view and projects the geometry to the view plane irrespective of the Absolute or WCS coordinate systems. That's why the geometry does not maintain the angle with respect to absolute when imported.
One solution is to either make sure that the view being selected for export is oriented correctly with respect to absolute, alternatively create a new view oriented correctly just for the purpose of exporting the 2D DXF.
Notes and References
Hardware/Software Configuration
Platform: INTL64
OS: window
OS Version: 764SP1
Product: NX
Application: TRANSLATOR
Version: V1847
Function: DXF_DWG
Ref: 002-7008379