It definately appears to be an issue between BackPress and WP about how the cookies are set.
One of the things i’d suggest would be to edit your bbPress login form to point to your wordpress login form but with the re-direct you want. That way no matter where someone logs in, it’s always from the same place. At least this loses the unknown factor.
Mental that we have to do this…
Easy integration with your blog
– https://bbpress.org/about/features/
the most important thing we need to figure out is how to integrate bbPress better with WP
Matt – https://bbpress.org/forums/topic/future-of-bbpress
