Torque missing

Hello, all.
I'm doing excavation simulate, to measure how much torque would appear.
I don't know why but all the time the buckets movement switches from move to rotate (rotate to move as well)
or to move meshes slowly, the torque suddenly drops. (not disappears)

It's happening on slowly movements, or switching movement.
(I attached only a case of slowly one, but switching movement would be the same result when switches the moves)
Is LIGGGHTS not able to express the state which meshes putting force to the particles without moving?
Or is LIGGGHTS not able to store the forces and refresh them when switching movements?

Typical input script's statements are shown below. (whole input script is attached)

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atom_style granular
boundary m m m
newton off
pair_style gran model hooke tangential history cohesion off rolling_friction cdt
pair_coeff * *
fix cad1 all mesh/surface/stress file meshes/bucket.stl type 1 &
rotate axis 0. 0. 1. angle 180. rotate axis 1. 0. 0. angle -90. rotate axis 0. 1. 0. angle 21.3 &
scale 0.001 reference_point 0 ${hwid} 0 stress on
fix bucket_wall all wall/gran model hooke tangential history mesh n_meshes 1 meshes
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I would really appreciate any answers.

Regards, George