So I found this question and edited its answer. However, it was only after I submitted a proposed edit that I noticed that the link given, specifically this link, points to a non-existent section of a wiki page. I checked it on waybackmachine and while the section existed as of the time the answer was posted, it was removed as of now. I've read the manga on that particular anime and I can say it's possible they removed it because some of the things stated were not confirmed. Reading further on the page, I noticed that they moved that particular section to a different one, providing citations while removing information that was not verified.
While someone familiar with an anime/manga can easily provide a better answer or just provide an updated link to the wiki page, I'd like to know how someone who is unfamiliar with a particular anime/manga should handle situations like these, especially if the sources are not wiki pages (pages from defunct websites that were not archived, online documents/paper that is not accessible anymore, etc.) Does this deserve a flag? And if it does, then I'd like to suggest an additional option in flagging, where the post can be flagged as an answer with out-of-date sources/non-existent sources/sources that cannot be verified. In addition, I'd also like to suggest a way for people to know that answers have out-of-date/non-existing sources (maybe a notice below answers stating that said-answer is already out-of-date or have sources that do not exist/never existed or a color aside from green, since I noticed this color is used for questions which already has an accepted answer, that would indicate that said post has out-of-date answers/accepted answers) so that people can easily identify them and can update the posted answer or provide a better one.
Anyway, this is just a suggestion. And, just to be clear, I'm not accusing the person who answered the question I posted as an example because clearly, it was not her/his fault to begin with (it was the wiki putting unverified information in the first place). Peace :)