Affects Windows 10 PC 0.14.0 Creative and Survival
When you try to toggle a lever* when holding a throwable item (splash potion, bottle o' enchanting, eggs, snowballs etc) it switches it extremely rapidly.
*The same happens with:
Comparators
Repeaters
Doors
Fence Gates
Wooden Trapdoors
Daylight Sensors
You can also reproduce this bug on android devices if you use a controller / gamepad.