Ok I joined a group and when got back to it to invite my friends it appears as if I haven't joined it (although when I go to see all members I'm there) and when I click to join this prompts:
And I haven't got the option to invite my friends to join because I haven't joined it!! It only appears immediately afterwards that I join a group but then when I return it disappears.
Damn! I have been also having problems to upload photos. In other profile that I made the profile picture sometimes disappeared. The weird thing is that with my personal account which I created before this cellphone verification thing nothing of this happens.