To reproduce:
1.Open attached project.
2.Open and run "ConfigJoint_DamperBug" scene located in Assets.
3.Select cube in hierarchy view and check its Configurable Joint component settings.
4.Try increasing Angular X drive > Position damper value, notice that instead of damping target rotation velocity it actually increases it.
5.Try changing Angular X drive > Mode, even if we change it to "velocity", position damper/spring settings are still effecting our cube.