I believe it just means that they aren't scanning it as it goes on its way. Or... that it got intercepted (sorry, but it is a possibility I think). The fact that it exists at all in their database means it was definitely at least introduced into the mail stream I think (as in definitely sent, even if it's just sitting there now). My understanding is that the tracking generally just ends if it gets pulled from the normal mail stream for inspection, but there's so little confirmed information that it's pretty sketchy to count on that.