I'm using 1.19 (due to MySQL restrictions on upgrading with host).
I already have one installation of Moodle running fine, however the new one (both fresh 1.19 and a copy of the existing) results in this problem.
When any user (including admin) creates a new discussion through the forum resource, instead of pointing back to the forum, it goes to /mod/forum/view.php (showing a 404).
Even the 'Continue' button points to /mod/forum/view.php (instead of /mod/forum/view.php?f=3).
If I refresh the 'your post was successfully added' page, it will then redirect correctly to the previous forum.
Any advice? It's driving me mad.