I have tried all you say, and it’s works !
Then i must have a bug or something bad on my website, i think it will be finish with a new install because i don’t see what is the probleme.
I have enabled Options de Notifications (In Settings/Buddypress/Components, all is enabled, in Settings all is enabled except “Enable group creation for all users”)
I haven’t touch anything in bp-custom or theme-functions, and more, i have tried the web site with many differents Themes, and with no plugin exept buddypress, and always the same problem.
I have tried in english, and i have the same problem.