1.7.1 old springs conversion bug

[Kilinich]

In 1.7.1 springs loaded from phun 5.28 sometimes just stop saving changes I made (hardness).
I've load it, then make many copies and they works fine but after save/load - copies weak again.
I'll try to reproduce in simple scene, can someone help?

p.s. With all that bugs I just can't make scenes in 1.7.1 I'm switching back to 1.6.0