Geospatial PDF Export Issues

I am trying to find a way to change the field that is listed in the model tree section of the PDF. If you look at the first image, you will see that each route is labeled by it's route name. If you look at the next image, the routes names are incomplete. The last image has all routes named feature.

I know I to control which attributes are exported by going to Layer Properties and selecting in the Fields tab. However, I can't figure out how do I control what is shown in the model tree.

Thanks for your help.

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