Verification builds:
1.1.0.9 Retail

Summary:
If an animal is leashed to a fence or a cobblestone wall, you are unable to place anything on the fence or wall.

Steps to Reproduce:

1. Leash an animal to a fence or a cobblestone wall
2. Try to place a block on top of the fence/wall

Observed Results:
Nothing can be placed on top.

Expected Results:
The lead shouldn't prevent blocks being placed above.

Screenshots/Videos attached: Yes

Notes:
It looks like the lead_knot hitbox is perhaps too big, or interfering with block placement.