There are small serrations on the clip or the plastic reservoir to stop it turning inadvertently in normal use.
If you twist the bottle you can feel and hear the clicks as the serrations move against whatever it is that stops it turning normally. The only way that the thing can turn in the clip is if the top has been butchered on wayyyy too tightly and has twisted the whole shebang as Chris admitted he had done.
One wonders if the dealers just let the apprentice do the job. For those of us who still use the dealers it is yet another thing to check before we blithely ride off into the sunset...