BoM/TWS Message Forum

I'm not aware of any chapters that provide definitive evidence one way of the other. That said, I've been careful not to murder any mask vicitms until after the mask came back out in the chapters I've written..

The copying and knockout components of the sigil are entirely separate. In some branches Will learns to use one without the other and vice versa.

So, there's no reason it can't copy immediately as soon as its put on, and no reason it can't wait to the end of the knockout to copy immediately before coming back out either. Just whether or not the Libra's author wanted to be awkward about it