Wordpress 3.6, using theme Twenty Eleven
BbPress 2.4 (Just updated this morning, though I had the problem with the previous version as well)
Only other active plugin: Error Log Dashboard Widget 1.0.2 (showing no PHP errors)
Several other plugins are installed, but deactivated while trying to debug this issue.

I have the following text on a single page:

Here is the shortcode for the single forum: [ bbp-single-forum id=39 ]

[bbp-single-forum id=39]

Here is the shortcode for all forums: [ bbp-forum-index ]

[bbp-forum-index]

The single forum does not display. The forum index does display. I have confirmed that the index is the correct number via the admin forum view. Here is a link to a screenshot. Here is the link from the forum page, showing the forum id: http://[domainremoved].org/wordpress/wp-admin/post.php?post=39&action=edit (Obviously, clicking it won’t work, because it requires a log-in, but this is to confirm that I’m finding the forum index correctly.)

Here is the forum: http://[domainremoved].org/forums/forum/pta-board/
Here is the page it is linked from, showing where the shortcodes do not work: http://[domainremoved].org/pta-board-2/
(Note: I have added spaces between the shortcodes so you can see the text that I used, then repeated the shortcodes without the spaces to display the forums.)

I feel like this should be some really simple user error, but given that I have double-checked the shortcode syntax and the forum id, deactivated all other plugins, and chosen the Twenty Eleven theme, I can’t figure out what it could be.

ETA: Wow, that was fast— my page got slammed with spam comments within minutes of posting the links here. I have removed them for now. If a support person needs them to diagnose the issue, I can give them out then.

[@campbellschool Participant 11 years, 3 months ago]

Coming back to answer my own post, in case it helps someone else down the line: the shortcode (for the individual forum ONLY) was distorted in Visual mode. Switching to Text mode and correcting the shortcode seems to have fixed the issue.

[@netweb Keymaster 11 years, 3 months ago]

ETA: Wow, that was fast— my page got slammed with spam comments within minutes of posting the links here. I have removed them for now. If a support person needs them to diagnose the issue, I can give them out then.

I have heard this a couple of times, I might set up a test myself, not sure what we can do though as presumably the spammers are just scrapping bbpress.org