I recently racked (23 days ago) a big brown ale on top of an oak spiral which had been soaked in bourbon. I broke the spiral in half before adding it.
Maybe a week later I noticed some bubbles forming around the floating spirals. It's obviously not still fermenting, I tasted it yesterday and nothing is wrong with it. All I can think of is that the spiral created nucleation points and caused it to foam. I would imagine this wouldn't be good in terms of oxidation.