Issue: Field shows text on Edit screen, but when record is saved, the field does not appear on the View page (non-Edit mode).
Navigate to Setup
Go to the Create > Objects menu
Select the Object that the Field is located on
Hover over the Field Sets Related List (at the top of page):
Select Edit next to the Field Set where you know the field is located.
In the upper left hand corner of the page, click on the name of the Field Set, and select the other Field Sets. Look through ALL Field Sets on this Object to make sure the Field is not shown in more than one Field Set.
Once you've found the Field in a secondary Field Set, remove the Field from the second Field Set by dragging it out of the box labeled "In the Field Set" and then click Save.
The Field is double-exposed (in more than one Field Set).