this is still a issue for me, because i have to update the role of new users everytime from the database when new user register to my site.
I found the the table inside database where it user role was coming, we need to change wp_capabilities value inside wp_usermeta table. This was the final solution to my issue.
Keymaster value : a:3:{s:13:"administrator";b:1;s:13:"bbp_keymaster";b:1;s:9:"translate";b:1;}
Participant value: a:2:{s:10:"subscriber";b:1;s:15:"bbp_participant";b:1;}
however, the value differs from site to site.
