I had a few entities on leads attached to fences, and when I killed the entities (horses, chickens, and sheep) they did not drop the lead. I haven't tried this with any other entities yet. The lead looked as if it was still on the fence, and also when I right clicked it, it didn't give anything.
Duplicate of MC-15084, please use the search function to see if your bug has already been submitted. Currently over 55% of tickets are being closed as duplicate.