I was using my foldable bicycle down in the sewers and noticed that sewage tiles randomly changed to water and dirt tiles as my bicycle passed over them.
Oh yea that 
The vehicle move code displaces water around to simulate splashing through puddles, but there’s no way for it to flow back in place, so the changes are permanent.
I love watching rougelikes being devd.
Most bizarre stuff is totally normal.
Whoa! its kind of cool that such things get simulated