Sorry for the delay in my response, but we are with many tasks.
We tried your solution, but it generated problems. Finally we came up with the solution, although it forces us to modify a small detail in the javascript code. To apply it, we must compile the assets with paver, independently, because when we did an update, it loads the original repository.
The change, is the following, in this line of the file
https://github.com/edx/edx-platform/blob/master/common/static/common/js/discussion/utils.js#L110We must add a
"/" at the end of this line, being as follows:
threads: '/courses/' + $$course_id + '/discussion/forum/',
If it works in a general way, it would be interesting to add it in the repository. We have tested it, in the native installation of ficus.3, ficus.4, and gingko.1
Thank you very much