Hello? (I’m Mkii user)
I tested the Cue output for the first time yesterday.
Oddly enough, the sound is only heard from the left side of the earphone.
Is the original Cue Out a Mono output?
Or is the panning setting wrong …?
And one more question.
Can not adjust the metronome volume?
Thank you for answer.
Headphones panning is ok with Main?
Headphone amp frequency response mismatch
There is a Metronome menu.
Project > Control > Metronome
Sounds like you out your Headphone into the cue 
stays in the phon, but you can adjust your cuing to be sent to the HPs that way. The cue outs are for routing purpose.
I have not tried it yet.
I will try this evening.
Thank you.