Piston-Pushed Observer Gives Constant Power

If I power a piston that is pushing an observer whose input-receiving side is against the piston head, the observer will power the block in front of it as long as the piston is extended, rather than giving off a 1-tick pulse as soon as the piston extends. This does not happen if the observer is facing a different direction. Also, this often won't happen until the second time after placing the observer.