This question already has an answer here:
I came across this question on SharePoint StackExchange and noticed that the accepted answer was ranked second:
Refreshing the page will swap it between first and second position randomly as if it just had the same votes as another answer and wasn't marked as accepted.
I've never seen an accepted answer in anything other than first position. The only strange thing I can see about this answer is that it appears to be answered and accepted by the same person that asked the question and that that person's account no longer exists.