The bug

When you right click a snow golem (or snowman) wearing a pumpkin with shears while you have another item with right click ability in your offhand, the item in your offhand is used as well.

How to reproduce

1. Spawn a snow golem with pumpkin
2. Put shears in your mainhand and an item with right click ability in your offhand, for example a fishing rod
3. Right click the snow golem
   → You will see that the snow golem was sheared but you also used the item in your offhand

Code analysis

Based on 1.11.2 decompiled using MCP 9.35 rc1

The method net.minecraft.entity.monster.EntitySnowman.processInteract(EntityPlayer, EnumHand) does not return true when the snow golem was sheared.