I have seen that a few times- usually it's reissued at a lower price, I have no idea how or why it's cancelled - maybe someone else can shed light on this??
On another subject.. as of this morning there were no shares available to borrow so it will be interesting to see if any are available tomorrow. Too bad the naked shorting makes it difficult to really know if short position is growing or shrinking... Either way message from company is that they will resolve short issue by creating value and increasing PPS!