Yesterday, I am pretty sure I accepted an answer given by a poster named HLKEM to this question here. However, just now I went back to add some relevant details, and the green checkmark signifying that the answer was chosen by me as been the best was no longer present. I am sure I did not remove it. The checkmark seen right now was placed there by myself prior to writing this.
Secondarily, the order of the answers seem to have been swapped. Although @Scaahu's answer has one more up vote (3) than HLKEM's(2), its been moved downwards in the answers listed. Usually, answers are rated in descending order by # of up-votes, no?
What could have happened?