i just tested this. works as i expect. i think the confusing thing is that fade is a rate parameter, not a time parameter. so the lower the number, the longer the fade.
to try it out, take something like the factory “space” scene as the starting point. this has a METRO resetting the read-head position for delay1 (which is pitch-shifted up.) use the leftmost switch in play mode to toggle input from adc0 to delay1.
the scaling isn’t quite what i would expect (and there are plenty of FIXMEs in the related code) but you should hear a distinctively softer transition on each METRO pulse, as you dial the value for fade1 towards the minimum from the inputs page.