Let's look at the following example to illustrate a common scenario I see with foundation displays:
Let's say you go into Object Styles or Visibility/Graphics and apply some graphical changes to the Structural Foundations category, such that the line weight is 4 and the pattern is Dashed:
You exit the dialog and notice some of the foundations changed, and some didn't:
A common reason for this is related to the View Range of the view. If your foundations are below the Bottom and within the View Depth they will display according to the
I hope this helps explain why this scenario might occur so you can understand how to approach it!