Pistons sometimes extends, even if no block is attached nearby

Sometime the Pistons are extending, even if there is no reason to do so.

This Bug can break Redstone-Constructions like Lifts, etc.

Mostly it happens randomly, but following Steps can reproduce it every time:

• Start from a high Point: build an column of Slime-Blocks downwards (see Pic ...01.24.44.png)
• Place a Redstone-Block (see Pic ...01.24.54.png)
• Place a Slime Block (see Pic ...01.25.05.png)
• Place a Piston or Sticky-Piston facing downwards - (the Piston extends imediately, even if it shouldn't) (see Pic ...01.25.25.png)
• Remove The Slime Block above the Piston - (Now the Piston should retract, but it keeps being extended) (see Pic ...01.25.29.png)
• Remove the Redstone-Block above  - (Now the Piston should retract, but it keeps being extended) (see Pic ...01.25.31.png)
• Remove all other Blocks  (see Pic ...01.25.41.png)

This Bug can be very annoying wwhile building Redstone-Constructions.