I am facing this issue from long time, tried in many ways but couldn't help myself much.
After exporting, if you open the exported DWG file in AutoCAD you will find many things are not converted properly.
One of them is-
Perpendicular dimension: It will become a 'BLOCK Referance' in AUTOCAD.
Do you have any solution to get rid of this problem?
First, make sure that you've installed the latest patches of your version of NX. You're more likely to get translation issues fixed in the latest release. If after installing the latest patches you find that you're still seeing issues, please consider contacting GTAC to get them reviewed. Usually a translation issue is a software issue or a limitation, rather than a user error. GTAC can test multiple versions, so if it is deemed to be a software issue they can check to see if the problem has already been fixed in a newer release of NX.
For your described issue, we had a similar problem reported for a perpendicular dimension, associated to a center mark, in NX8.5.2 using the 2D Exchange translator. This was resolved in NX9.0.1 and now perpendicular dimensions are translated as "Real" dimensions. However, perpendicular dimensions are not supported as "Real" when using the DXF/DWG translator, they will always be translated as "Block" references. While this doesn't help you, at least you now know it is a known limitation.
I feel it's not a issue then, it's might be a limitation.
Still I rise this issues of conversion in GTAC as you suggested.
Thanks a lot.