Put the summary of the bug you're having here

What I expected to happen was...:
the lead would disappear when i broke the fence it was on.

What actually happened was...:
it did not disappear for at least 10 seconds.

Steps to Reproduce:
1. make a fence pole 10 or 9 fences high
2. place a lead on a cow
3. place the lead on the fence then break the fence that the lead is on