That may well be, but a php check by my hosting company says there is a lot of deprecated or forbidden code in the following files:
/bp-forums/bbpress/xmlrpc.php
/bp-forums/bbpress/bb-includes/backpress/class.bp-log.php
/bp-forums/bbpress/bb-includes/backpress/class.ixr.php
/bp-forums/bbpress/bb-includes/backpress/functions.core.php
and so on…
Maybe it has something to do with the BP Activity Privacy plugin; in Profile Activity privacy there is no option to make updates visible to group members. Updates set to “Logged in users” appear, updates set to “Group members” don’t.
I use a child theme derived from the default team, only changing the visibility of the menu as explained in //https://buddypress.org/support/topic/resolved-hiding-navigation-links-for-buddypress-pages-for-non-registered-users/
When I use the default theme as such, it still doesn’t work.
I also tried to change the user’s role to author; still no luck…
Similar problem here: WP 3.5.1 multisite + BP 1.7.1
When admin accepts membership requests all works well; new members are added to the group list. But the new member doesn’t actually get access and still gets a message that says “this is a private group, request memberhip”.
I also use the DB Cache Reloaded Fix plugin.