loosen the pivot allen keys and push it tight towards the closing cam. then tighen the grub screws to hold the pivot in this position. It should cure it.
If the grub screws are mot tight then the pivot will move to a loose postion again. Tighten up the pivot so moving the bars in to the folded postion is "firm", but not so tight they are locked in position!!
Hope this helps. Its a bit fiddly but in my experience the play can be adjusted out.