Cannot Assign Feature Definition after Dropping Complex Status

I encounter odd behavior sometimes when dropping the complex status of a complex element of horizontal geometry. Unfortunately, I cannot recreate the issue in a repeatable manner. When I drop the complex status of an element, the feature definition of the individual elements disappears. Furthermore, when I go to the properties of an element I cannot reassign a feature definition because the feature definition portion of the properties has disappeared. Does anyone have any idea as to why this happens and how to correct or prevent it?