Set Sound Mix Class Override to a volume of 0 causes sound to permantly mute (?)

I have a volume slider set up in the UI which uses the “SetSoundMixClassOverride” node with the slider’s value as the volume’s input. It works until the slider goes to (near) zero and then the sound mutes. Moving the slider back up has no effect. The mixer retains the 0 value and won’t un-mute. You can raise and lower the volume as expected so long as you don’t go all the way to zero. What’s happening here?

I have the same issue

@Whammy dis you solved this ?