I had this same problem with disappearing menu text.
Bottom line, I applied a different theme to the menu page by dragging and dropping a theme selection from the Themes tab to the Menu window. I then reconstructed the menu. The menu text did show up upon burning to disk after that.
Things I tried to adjust that did not fix the problem are as follows:
1) Individually deleting and reinserting every menu item, like backgrounds and labels.
2) Changing selection highlight masks.
3) ‘Bringing to Front’ of selection buttons.
4) Changing fonts/sizes on the buttons.
5) Making sure highlight masks were not overlapping.
The preview in DVDA functioned perfectly. It was only after rendering/burning this error showed up. A frustrating aspect was that only the main menu was acting this way. I could navigate the main menu and the highlight mask would show up where the labels were, but the words would not show. Other than that, the DVD worked fine.