lost image at fast speed

[CarlDegio]

I found a render bug in tacto. In my scene, I add an UR5 robot and a small sphere (same in tacto example). I control robot to push the sphere. code in here. In here, I set a push speed by ik, desire_pos[0] += 0.0009. But at this speed, the tacto sensor can't get useful tactile image, like this:

If I change this speed as 0.0004, things will change:

In fact, I think the faster speed lead to the stronger contact. But the bug of tacto makes it strange.