Can you please try the following:
1) Close rekordbox. Launch 'Font book' from the Launcher. Click Command-A to select all fonts, then select 'Resolve Duplicates'. Close the Font Book, re-open rekordbox and test.
If that doesn't work...
2) Close rekordbox. Open Font Book, select 'Validate Font' from the File menu to check fonts on the system are not broken. Close Font Book, open rekordbox and test.
If that still doesn't work...
3) Close rekordbox, open Font Book. Select 'Restore Standard Fonts' from the File menu. Please note that this will remove non standard fonts from the system (actually they are put aside in the Fonts(removed) folder. So they will not be deleted). Close Font Book, open rekordbox and test.
Let me know if any of those steps helped.