Sticky Pistons do not stick to glazed terracotta

Sticky pistons do not stick to glazed terracotta

What I expected to happen was...:
The blocks would stick to the piston so I could make a piston door.

What actually happened was...:

The blocks were only moved once and did not stick like with a normal piston.

Steps to Reproduce:
1. Place sticky pistons with any kind of glazed terracotta on the green end 
2. Attach a lever or button
3. Pull lever