Problem RTF output:  

The class list  classes within the namespace report is wrong indicated.
There is some confusion in indication of classes and their brief description.
The HTML indication is correct. 
The error can be easy recognized if following screenshots are compared. 

See the screenshots: 
2017-06-28 11_28_51-Error sample_ Error Namespace Reference_HTML.jpg 
2017-06-28 11_26_06-refman_RTF.jpg.  (shows the error behaviour)

Used versions:
Doxygen version: 1.8.5 also tested with 1.8.13
OS:  Windows 7
Microsoft  Word 2010
The folder contains the error sample.