Missing Construction Line from SMT

Yesterday, I was working on a diewall using the Solid Modeling Tools. At the end of the day, I saved my work and shut down my machine. Today, part of the diewall is missing from the drawing and I can't figure out how to get it back.

The diewall consisted of two construction paths because there are two section details, both a high wall section and a low wall section. When I saved and shut down yesterday, I had one of the products unchecked in the Tree View so that it was hidden. Today, I can't restore the one that was hidden because the construction path is missing. But, here is the funny thing...

The 2D Polyline construction path exists in the drawing, but it is simply INVISIBLE! For the life of me, I can't figure out how to get it to show in the drawing. I have attached two screenshots to demonstrate what I mean. The first one shows that if I use Quick Select (QSE) to select all objects on that layer, there are two (2) 2D Polylines. In addition, the UCS indicator appears at the midpoint of the overall length of the two 2D Polylines. See screenshot...

Missing Construction Line

For the next screenshot, I did a reverse window selection to make sure the two lines were not on top of each other. As you can see, there is only one 2D Polyline. See Screenshot...

Reverse Window Selection - Only one 2D Polyline

Does anyone know how to get the Construction Path back? Perhaps related to that question, does anyone know what Microvellum actually does if you uncheck an item in the Tree View of SMT? What command is actually used to hide and restore the objects as they are checked or unchecked?

I am really hoping someone has seen this and can help me. Thank you!

Edit 1: Also, I did confirm this by using the dxfout command to write out a dxf file. Then, I imported the dxf into Alphacam and both construction paths are present. See Screenshot...