Unchecked legend items from map services are showing in exports.

Solución alternativa

1. Add data from a map service. Use data from the path with REST endpoint or use Portal in the Catalog pane to add to the current map.
2. Insert a new layout to the map, for example, a letter-size layout. Add a map frame from the current map on the layout and leave space for legend. 
3. Keep all the layers within the map frame checked and visible. 
4. Click Legend and create a new legend on the layout, include all legend items on the layout. 
5. Uncheck one or several unwanted legend items, and ensure the unwanted legend item is not displaying on the layout.
6. Right-click Legend under Drawing Order, and select Convert To Graphics. 
7. Export layout as PDF file type with default settings or the user desired settings.
8. The PDF file of the layout displays the legend items correctly. 

Pasos para reproducir