I find several questions like mentioned here: Question of deleted user shown The question OP is not clickable (and often has a name like user123456) and is probably not existing anymore.
These questions become orphans with respect to control over the accepted answer when the OP is gone.
Often the orphans are ok, since the 'accepted answer' is (I believe) considered from the viewpoint of the person that asked the questions. So when that person is gone then we might say we do not care about the accepted answer.
(A bit of track: from my viewpoint the 'accepted answer' is not only about the benefit to the OP and it serves a wider purpose. Because of that it should in my opinion should be controlled by the community and not just a single person. This is especially the case when the OP that asked the question, is possibly having a knowledge gap, and may not always know what a good answer entails, especially what makes an answer a 'correct' answer. But that's a different issue)
What do we do with the control of these orphan questions, and especially when the accepted answer is false? (but there is no OP anymore to change this)
This question can be taken as an example case: Statistical language in "The Avengers" It's 3 years old and has an accepted and upvoted answer, but... does that close the case?