The jive was Rachel's best dance, it started really well and she was smiling and looking as if she was really enjoying herself - or at least pretending to, which, from the 'watchers' point of view amounts to the same thing.
But then it went flat and the sparkle vanished, not sure whether this was because of mistakes, or timing issues. Whichever, there were far too many 'stops' between moves, which made the routine look jerky. (Didn't think Rachel deserved to be above Jodie on the leader board.)