I'm sorry so much time has past on this issue!
I tried reproducing the problem by duplicating various raptor bone (leg, hip, etc), but it worked fine. I'm guessing something about the complexity of your skeleton is causing the problem. I'm very interested to know what it is! If you could please post or email the .spine file, that would be very helpful: contact@esotericsoftware.com You don't need to send all the images.