I got this weird bug the other day, I was downloading a movie, and I turned on play while downloading.
And suddenly the percentage went sky high (and kept counting) while the filesize kept decreasing (even going negative), and the files were not being unpacked.
I don't really know what made this happen, but it happened. If you can't translate the dutch at the top, I am using the latest version. (Also to be checked in caption bar).
Don't know if it matters, but I'm using win7 64 bit.
Link to screenshot: