Redstone dust connects directly to pistons.

In versions 0.15.0 - 0.15.2 redstone acts normally. But in versions 0.15.3 - 0.15.9 redstone connects directly to pistons as shown in one of the screenshots. This doesn't happen in Minecraft PC because if it did it would make redstone less compact. If you wanted to run a wire alongside a piston it would need a one block gap or else it will disrupt the piston. You might think this is good but most of the time it causes many problems when building with redstone.