I've managed to reproduce this crash. It crashes when playing a video file on the same harddrive that is being written to during a download. The file is mp4, the harddrive is connected via "artificial" USB3.0 (Expresscard USB3.0 with powercable), and the download IS p2p.
The crash: things freeze up first, then screen goes blank while switching black user-login screen (userspace).. then message "caught signal 15" and shuts down. It has done this twice so far and is excessively annoying. All I want to do is learn true american history....... ugh. lol