"New user doesn't mean unexperienced."
Unfortunately this seems to be a problem with most long-established forums.
I use a forum in a different field which suffers from exactly this issue, with the additional problem that most of the long-standing members also act as moderators.
There is one particular question on the site where the answer given has a potentially devastating race-condition. Unfortunately this answer is considered to be an elegant solution by the member who posted it a long, long time ago.
Technology has since moved on and there are now far simpler (and safer) solutions, but any user who tries to point this out either gets their comments removed, or a very blunt reply pointing out who has been on the forum longer.