Hi and thanks for posting this. It could be a bug, but the appearance of two players is usually caused by "double filtering." (I made that phrase up, but I get to use it a lot, so its ok.) Here is how I described it previously.
The appearance of two players is caused by "double filtering." The link to the media file, is parsed by both the multimedia plugins filter and the PoodLL filter, so both try to turn it into a player.
In most, but not all, cases moving the PoodLL filter higher in the list of filters than the Multi media plugins filter solves the problem. When it doesn't, usually because the media file is being used in a "label," disabling the file extension (mp3, or mp4 or whatever) on the multi media plugins filter (site admin->appearance->media embedding) will fix it. For PoodLL you can disable the file extension at site admin -> plugins -> poodll filter settings.
You could also turn either filter completely off which would solve it. But there are reasons to keep the multi media plugins filter. As an example, because it will turn links to YouTube videos into Youtube players.
That you mention it occurs in labels, is a pretty good sign that we have double filtering going on. Try turning off the file extension in question (.flv) in the Multi media plugins filter, and see if that fixes it. If not, report back and I will dig into it some.