If you change the original values of 0 and 1.0 to say 0 and 0.5 and enable oscillation, and then go and disable the range min/max option, disable oscillation, and then re-enable oscillation, the 0 to 0.5 settings will still persist.
It may be design, but I would expect the upper range value to change back to the default of 1.0 when the range option is disabled.