My form displays a field in black font when in view. When the user selects Edit Item, the field doesn't show. However, when the user highlights the contents of the field, it's there (in light blue font). The field type is a single line of text. Other fields with the same characteristics in the form work fine. I tried using Format Painter to copy the format from one of the fields that behaves, but that didn't fix it.
After some further trial and error, I was able to fix it. The field is in a panel, and I discovered that when I changed the font of the panel to black, the field now appears in black font when in edit. It appears the panel font was somehow overriding the control font for a few fields.