Configurable Joint's Angular Drive's Position Spring's infinite value tries to assign transform.position to {NaN, NaN, NaN}

Steps to reproduce:
1. Open attached project's scene "simple_rig".
2. Enter play mode.
3. Observe errors in the console:
transform.position assign attempt for 'cube child' is not valid. Input position is { NaN, NaN, NaN }.

Should be fixed in 5.2.