In most cases, I’d like to think that they are found and corrected (like your example above). That is a big reason why what we see reported each hour is not yet ‘certified’.

The fact that recounts typically are so close to the certified counts is very encouraging that we’re pretty good at these counts. But sure, it is possible for mistakes (or intentional acts) to carry over through a recount as well.

Intentional acts just seem unlikely to me due to the gigantic legal risk of being nefarious.