Undo "Multiply" on a pickup machine

Hello,

Sometimes, while using a Pickup machine, I hit TRACK + MIDI by accident and it activates the MULTIPLY command (ie. the lenght of my loop is doubbled).

Does anybody know a way to UNDO this “multiply” command ?

If I am in a studio I can go in the EDIT menu and crop the loop, but in a live contexte it is not a good solution (too long to get the right end point).

I hoped the “multiply” command would maybe cycle and come back to the initial lengh, if I press TRACK + MIDI again and again, but… no : it only goes until the record memory gets full.

Any idea ? Thank you for your help !