Hey there, My Ingamename: Smaragd27 Server: Node 4 I killed the Draconic Evolution Ritual Ender Dragon two times now. And the Heart didn't show up. I think thats a bug. I had a hard time to farm the 800.000.000 RF and the 8 mob souls so i just want to say that i explored this bug...
The dragon heart will often "activate temporarily" when you kill the dragon, which will make it float where the dragon died. It will take a few moments to de-activate, and then you can pick it up. Try going back to the location, and hopefully the heart will be on the ground then.
Happend the same to me, lost time and 4 souls + 4 charged draconium blocks... And I have another bug during the awakening of the draconium blocks, it drops me the heart after the ritual + 4 awakend draconium blocks, it's an advantage bug, cause I have infinite dragon hearts! If any admin/co-admin/mod want to see the bug, no problem, teleport to my base and I'll make the ritual again.