Steps to reproduce:
1. Create a price set. In my test I created a price set called "Theatre Tickets."
2. Add one or more fields to the price set. In my test I created two text fields (Child and Adult).
3. Create an event using the above price set.
4. Register one or more participants for the event.
5. Search for the event participants using "Find Participants."
6. Export the participant list.
In the "Find Participants" search results, the "Fee Level" column correctly shows the fields and values from the price set associated with the event. However, in the exported results, the "Fee Level" column is empty (on the 2.0 sandbox) or contains the event name (on 1.9 final release).