Hmmm...that's strange.
When in light edit mode, make sure the mute button light is off. If you want it to save, you need to make sure you don't switch the amp off for at least 5 seconds so that your change is saved.
If that still doesn't work, you can power the amp on while holding both the mute and kosmos buttons to reset everything, then try to change them in edit mode again.
When in light edit mode, make sure the mute button light is off. If you want it to save, you need to make sure you don't switch the amp off for at least 5 seconds so that your change is saved.
If that still doesn't work, you can power the amp on while holding both the mute and kosmos buttons to reset everything, then try to change them in edit mode again.