[0.12.1] Weird thing - Removing path reveal water

[Ohz]

Hi guys, I started a new map at 0.12.0 and built my factory, and some stone brick path.

Then I upgrade to 0.12.1 and I was just removing the path when this appeared (so while removing tiles of stone brick). There is now magically water.
Weirdest bug I ever seen.

Screenshots

And my savegame:
http://dl.free.fr/pJtVXB9vO

I use only marathon mod.

[FishSandwich]

Dup: https://forums.factorio.com/forum/vie ... 30&t=14068

[Ohz]

Thank you