Hi,
First, sorry for my English, I speak french 
I have a QU-24.
With the multi track recording, I can record the 18 first tracks. But, I have seen that I could assign for example the input 2 on the track 1, the input 20 on the track 2, …
When I record on USB key, that’s not working… It continue to recording only input 1 on the track 1, input 2 on the track 2,…
Me, what I want is to record 18 tracks that are spread over 24 entries.
Is it possible?
Thank you for your help 
Absolutely it is - are you overwriting your assignments with scenes?
Maybe forgot to press the apply button after changing the assignment (Setup->Output Patch->USB Audio, Manual Section 8.14)?
No, I have a scene for this and I make “apply”… I don’t understand
I’ll try again tonight
BTW… Your English is VERY good. I wish I spoke French as well as you speak English !!