I see why. They changed it. Before it was redirected to a page and the error was there. Now it shows a JS alert. Anyway, the error is now logged:
}
catch ( \Exception $e )
{
\IPS\Log::debug( $e, 'content_debug' );
\IPS\Output::i()->error( 'edit_no_perm_err', '2S136/E', 404, '' );
}
See the debug there. So go to ACP -> System -> Support -> System Log and the error has to be there.
I, for example, renamed the column forums_posts.post to forums_posts.postX then I got the alert but the error is in the log:
Check your logs.