The bug

When you push an amethyst cluster off of its supporting block with a 1-tick pulse (such as from an observer), using a sticky piston, the amethyst crystals don't drop, whereas if you push it off normally they do.

Steps to reproduce

1. Place a Sticky Piston
2. Place an observer facing into the piston
3. Place an Amethyst Cluster in front of the piston
4. Power the observer
   → Notice how the amethyst crystals do not drop but instead, the block just gets deleted

Alternate Method

1. Set up the situation in the attachment
2. Place a lever on the side of the sticky piston
3. Flick the lever
   → Notice how the amethyst crystals do not drop but instead, the block just gets deleted