Aperture photostream duplication!

Everytime I try to manual add a photo to photo stream through Aperture it doubles every other photo on photostream. If I have 10 photos and I try to add a photo I will get 21 photos... 2x10 (old photos) + the new one. And it keeps this way everytime I try to add more photos. However, in my iPhone and iPad there is no duplication.

When I close the photo library and open it back again the problem is solved... However, this is really anoying! I already removed iPhoto on iOS and cleared the iCloud photostream but the problem persists.

Any suggestions?

Thanks!