"it is not a bug, Cross Porter can miss the timing (as hinted by the "when" in the effect), so for triggering, Cross Porter being sent to the GY need to be the last thing to happen
Hand destruction Discard then Draw 2, the last thing to happen is the draw, not cross porter being sent to the GY
more information in the following link:
http://yugipedia.com/wiki/Missing_the_timing