This could be automatic. I noticed this myself because I corrected
both typos in english and german wikipedia; sometimes they are
reverted, sometimes not. There seems no logic in it, so I assumed
that in some cases this must have been automatic wiki bots
reverting something.
The main anti-vandalism bot ClueBot was created in 2007, and its successor ClueBot NG in 2010. They certainly have false positives from time to time, but that doesn't mean they aren't the most useful bots on the website.