Hello, I don't know if its a Media Youtube's issue, or a Media Internet's issue, I haven't seen the code.
If you try to upload a video (from the file/add/web menu) and the video in its title has a dot at the middle of the title, e.g: http://www.youtube.com/watch?v=GTDIVnQsxq4
The extension will be the part after the title. So you cannot edit it, because the extension is disabled, but the video is already saved and you can click on the 'view' tab and watch it; if you go back to edit that video, the extension is gone and you can happily edit it.
I hope this information is enough to reproduce it.
Thanks for the module!!