(This also was also reproduced on an iPhone 6 Plus, same iOS version, same Minecraft version, 1.2.5, released Nov. 22, 2017)

When I placed down a powered piston for my table in my house, I accidentally destroyed it. But instead of just disappearing, a piston item dropped.

To recreate the bug:
1. In creative mode, place down a powered piston (sticky or normal, doesn't matter).
2. Destroy the piston head when it's extended (the extended arm part of the piston). Destroying the base or the unextended head doesn't recreate the bug.
3. The piston item will drop.