Alien races challenge

Hi Mi-Clos and every one
I've been playing this game for quite a while, finishing all 3 endings, all I need to completely beat the game are the challenges.
And this is were I encounter a bug: no matter how hard I try, I just can't meet more than 6 different Alien Races during a game.
This mean I can't complete the 3 challenges (encounter 10, 15 and all aliens races).
I've tried (and I believe i succeeded) to explore the whole galaxy with a fully upgraded spaceship but nothing seems to be working and I remain blocked on this number of 6 Alien Races On. Every. Single. Game. I've. Played.
Is someone having the same problem as me? I've looked rapidly on the forum and didn't found a topic referring to this problem but if the solution is out there () I'll be more than happy to have it.
If this helps I'm playing on iPhone 5 iOS8.2 or iPad 2 iOS8.2
The game remain awesome and I can't wait for the omega update.
Peace.