Disappearing curves

I ran into a very perplexing issue.

I have an assembly in which I've exported a top and bottom die.

Each die has curves that need exported as an IGES or STEP (along with the rest of the geometry).

The bottom die exported fine, but the top die did not export any curves.

I made the discovery that the die itself was responsible.  Any time a curve was generated it would automatically hide the curve.  As soon as I made a sketch, copy geom curve insertion or curve projection  it would end up hidden.  I could unhide these entities in layers but they would not export out.

In the end I placed a curve on a plane in the assembly itself and it did export properly.

My thought is that there is a settings issue, but I have no idea why or what it might be.