More information?
The piston is pushed after a block update (When an adjacent block changes state in some way, the game updates all adjacent blocks) and this behaviour is so old that I think they will not change it anymore. Also it would break many redstone contraptions that rely on this mechanic. The piston also doesn't move because it doesn't realise that a block has been broken and it can extend (because again...) it doesnt get an update.
Do you have more info?