BuddyPress.org

I don’t know if anyone is still following this thread but I discovered the users with this problem had not activated the account. So I installed this plugin so I didn’t have to keep deleting and recreating these accounts. https://wordpress.org/extend/plugins/wp-activate-users/installation/
FYI the users either were not receiving the email, or so they say, or the message went to spam or didn’t activate when they clicked the link.
hope this helps.
chow