Terrain depth bugging out

Wanted realistic snow, was a success mostly:
"SNOW" : {
"staticFrictionCoefficient" : 0.55,
"slidingFrictionCoefficient" : 0.35,
"hydrodynamicFriction" : 0.01,
"stribeckVelocity" : 2,
"strength" : 1,
"roughnessCoefficient" : 0.5,

"fluidDensity" : 400,
"flowConsistencyIndex" : 2000,
"flowBehaviorIndex" : 0.5,
"dragAnisotropy" : 0.45,
"shearStrength" : 4000,
"defaultDepth" : 0.8,
"collisiontype" : "MUD",
"skidMarks" : false,
"aliases" : ["mud", "snow"]
},



Depth map is set to be nearly bottomless pit, that is quite black, to get snow enough deep combination of deep depthmap and above settings were required.

That creates a bug where entering inside the terrain at entrance of tunnel can have one spot where terrain acts like super strong magnet.

It is just one spot at location of tunnel entrance/exit at position where terrain is cut, as can be seen on video.

Technically might not be a bug in game, but limitation of code as I am efficiently exploiting mud code beyond what is designed to do.

This is desired effect, which is why such setup was required: