It's possible to delete an individual curve label. Maybe someone accidentally deleted that one label. Have you tried to import the label set again?
This was an initial curve generation. The profile had tangents with no curves. I even created a quick profile in the same profile view and generated a couple of curves and multiple sag labels showed.
and here's something i just noticed, the profile properties doesn't give the option for update status. The cell is blank and when i click it....nothing, no options for dynamic or static.