Corgi-L is a moderated list.
While some of the moderators seem to sit at our computers all day just waiting for posts to approve, the reality is that we all also have lives. If we’re going to be busy for an hour or two, we’ll deal with pending approvals when we return.
So delays of up to an hour or so are possible, but it’s usually quicker.
If your post touches on a potentially controversial or sensitive area, the moderators may discuss it among themselves prior to taking action. That can also add a delay.
Finally, it’s also possible that various anti-spam measures can also randomly introduce a delay.