What I expected to happen was...:
Blocks breakable by the enderdragon would only break if the dragon moved through them.

What actually happened was...:
Blocks well below the enderdragon's hit box are being broken.
The enderdragon is flying around above the end island (>y=64) but stone (or other dragon breakables) are being broken below y=30.

Steps to Reproduce:
1. Place a solid chunk of stone blocks below y=30 near 0,0 in the end
2. Watch enderdragon's position and note any changes occurring in the stone layer despite dragon not touching them.