Double Tallgrass Changes To a Peony

What happened was:
When I broke the bottom part of a Double Tallgrass, the top portion changed to a peony flower for 1 or 2 ticks. It sometimes takes 2-3 tries for it to actually happen.

Steps to Reproduce:
1. Find 2 block tall Grass
2. Break the lower block of grass
3. Quickly look at the top block