Z2 + remix decks problem?

I've had the Z2 for a bit now, but I've only just dived into the remix deck triggering options it has. I'm having a bit of a problem though; the 4 launch buttons that are supposed to trigger the first sample in each remix deck column (if i'm not mistaken), seem to just pick samples at random to be triggered from the four pads on the z2. Any idea why this is happening?