I believe this is new to 1.5.1 and not duplicate.
In 1.5 there was a flickering with item counts under 10 units in the inventory or hand etc, this flickering has now passed to the head texture of sticky pistons.

Occasionally sticky piston head textures are either flickering every few seconds (in inventory, selection row or hand) or changing completely whilst unpowered and unconnected.
This seems just to affect sticky pistons rather than regular ones.

Will try to upload gif etc of the flickering inventory/hand sticky piston later.
Attached some images of static (completely unconnected) pistons changing to a glitched texture when another nearby block is placed.

When nearby blocks are updated the textures normally fix themselves or this glitch jumps to another piston.