Live mirror repeat - how to release strokes?

I've been using the 2021 feature for live mirroring but does anyone know if it's possible to release the live mirror mode so that the sketch becomes normal strokes again?
When I click Release from the menu, only half the mirrored sketch stays. 
When I click Expand, the strokes expand into shapes, but I want to keep them as strokes!

Basically I want to keep the whole mirrored sketch as normal strokes and then add details to it without it being in Mirror mode anymore. Hope that makes sense! 🙂