On our forum (synthforum.nl) we use the SoundCloud embedded plauyer, the simple one, I forgot the exact name of it. Since a few minutes, tracks aren't visible any longer. There is a message in the player: "Please visit SoundCloud.com to listen to this content". I have not seen this before. We haven't changed anything within the forum software.
Forum software is vBulletin 3.8.7