NX NC Machining Item type does not open in NX Manufacturing.

NC Machining item type is created inside Teamcenter.

This object when opened in NX does not open the Manufacturing Template by default.

Instead it opens in NX Gateway.

The NC Machining item created without a NX Part file(dataset) shows this behavior.

To resolve this issue, you need to  make changes in the Customer Defaults of NX.

Go to:

File -> Utilities -> Customer Defaults -> Teamcenter Integration -> General-> Parts without NX Datasets -> 

Display Select Template Dialogue Box -> Yes