sorry for a delay we have take a look at the issue you are having and it seems that is't working properly on our side, please see the attached images. Maybe it is a misconfigured web.config rewriting related to discussion board tags and groups, please check that.
Also, how to hide/disable Back to all discussion boards in the group discussion board?
Please note that MonoX built-in groups doesn't have multiple boards enabled so I don't see how you can get the "Back to all discussion boards
" inside the groups, please elaborate in more detail ?