It is possible for default journal security options to be configured in such a manner that would prevent group journal items from appearing properly.  For example, if the default journal security option is set to Friends only this would force all group journal items to have a security setting that restricts visibility to only the author of the group post.  

Workaround until patch:
Change default security option to Default, Community Members or Everyone.  Any other setting will cause problems with group items.

Solution:
An additional security check has been added to group journal items before being saved.  If the security being submitted prevents the journal item from being visible it will be reset to the default group visibility.