Infinite Sticks by Shearing Dead Bushes

What I Expected:
To obtain dead bush by using shears

What actually happened:
I obtained dead bush as expected, but still dropped sticks as if I broke the block without shears

How to recreate:
1. Get shears and dead bush
2. Plant or find dead bush
3. Shear dead bush
4. Re-plant obtained dead bush
5. Repeat steps 3 to 4