Merlin negative G cutout too quick?

[klem]

I am finding that the Merlin engine misfires at the slightest nudge down of the nose, nothing like a nose pushover. This also happens in level flight with some slight movement say due to turbulence or a mere touch of the stick however much I adjust the Mixture.

Can this be correct? We all know the story of negative G and the later Tilly Orifice but would our Fighter Aircraft engines ever have been so susceptible to Negative G that it is impossible to fly them straight and level without them constantly misfiring/puffing black smoke?