I built a farm in Minecraft Windows 10 Edition, a big farm with water and pistons.
The pistons are supposed to block the water from flowing over the field, but while sometimes when I save the world and then reload the world the water would be flowing over my field.
i suspect that somewhere when saving or loading the world, the water is in the world but the moving part of a piston has not been loaded yet, so the water starts flowing over my field.
I happened to expierience this while i was livestreaming, so I do have a recording of my expierience.
Here is the tweet with the video