Character joint. Spring does not work.

Hi!
I have a problem with springiness of character joints.

“Spring. The spring force used to keep the two objects together.”

I change this values, but nothing changes.
132097-screen.jpg
Joints are stretching like a rubber.

Maybe in one frame, force is applied only to 1 joint?
And other joints are calculated in next frames, and always late?
So, if adding too mach force, always will be stretching?

Or maybe some option in some place need to be on?

Maybe developers know?
Say something please???

When using the character joint, you want to use damping to control the oscillation, you can control it by setting the Drag property of Rigidody