The answer gets marked as correct only in 2 scenarios:
You can always mark the answer as incorrect and reopen the question.
Hope this helps
@crich2784 Thank you for sharing this feedback.
We are internally planning to streamline this process. Currently, tons of users don't mark answers as correct or reply on top of the thread.
As a result, we started with the purging of those threads (extracted from a tool). Sometimes it happens that even very new threads also get purged. We will update this tool to make changes in the filtration part to not pick those threads that are very young.
Really appreciate your feedback and we would work on it. BTW, the author of the post can unmark the answer as correct.