An update can accepted or rejected. Check the History Tab to see if it was successfully accepted by the reviewer or rejected. If it was rejected there should be a rejection reason listed.
Or you forgot to add the video ;). In this case just resubmit the update.
Strange. Usually you can see changes instantly after update approval.
I suggest you to wait a bit more time, if the video will not appear you can submit a new update (with the mention to update the video), then if this does not solve the problem you can submit a ticket to Envato Help Team.