I have a large assembly containing several parts and subassemblies that I want to export into a .STEP file as well as a .SAT file.  In the past, when I've exported, I've had no problems.  For some reason, as of yesterday, any time I export the model, it is missing a huge subassembly when I open the export file.  Now, this subassembly is not suppressed or hidden when I do the export, so I have no clue as to why it disappears.

Is there some setting that takes out a part or subassembly in an export (other than suppressing or hiding it)?  I have no clue what's going on here.

The subassebly that keeps disappearing was brought into my model as an imported .STEP file saved as a Solid assembly, not sure if this makes any difference.