Laser engraver cant pick up cut lines on print merge

I am 2 days into using X6 instead of X4 attached to my trotec engraver,  using XP.

All goes well with the print to the trotec job control, with it picking up the red vector cut line.

But if I print multiple pages, or use print merge (which is essentially the same thing), the cut line only prints as red on the first page.  From then on the print line is some grey colour and consequently the laser does not pick it up.

Have tried changing colour conversion to the Trotec, but this doesnt have any effect.

Anyone have any clues????