MyBB

From profile there are 2 options.
1. Find All Threads
2. Find All Posts

If you have limit set for search results.

If you Find All Posts the results display the newest posts first.

BUG: If you Find All Threads the results display the oldest threads first and cut off the new threads because of order.

If no limit is set then the search results do indeed display newest threads first. So this is related to limit.

You can see example from HF on my own profile.

Possible fix:

search.php

@if(intval($mybb->settings['searchhardlimit']) > 0) {
$limitsql = "LIMIT ".intval($mybb->settings['searchhardlimit']);
}@

Change to:

@if(intval($mybb->settings['searchhardlimit']) > 0) {
$limitsql = "ORDER BY t.dateline DESC LIMIT ".intval($mybb->settings['searchhardlimit']);
}@