On the road from electro to mogilievka on the map between [9880.79 | 4588.36] and [9375.25 | 4888.77] assuming you are heading to mogi, on the road on the left there is a little river. if you go near it the player starts making a floating / fallin animation and gets kind of stuck in the air, while being next to the water, or almost on the road. Its not inside the water. If someone is lookin at you you look like you're swimming. In your screen you're not swimming though.

Essentially it looks like the water is interfering with the ground and stuff outside the place where the water looks to be.