Avatar or Expansion of Krishna: Kalki

                            Q. 1. I'm confused on the subject of yuga avatars in this cycle of Kali. Gaudiya Vaisnavas claim Sri Caitanya Mahaprabhu as the avatar for this particular cycle of Kali yuga. Since he has already appeared, will this kali yuga end without the appearance of the Kalki avatar? This seems to contradict the Vishnu Purana.