Camshaft design (valve event timing),valve jobs,and header efficiency all can affect it.
You can have a ton of overlap and never see signs of reversion if everything else is right.
I am finishing up testing 12 different camshafts in one of my engines,one of them had signs of reversion in the intake runners.
It was the one with the least overlap of all the cams tested.
It has a lot to do with the rest of the valve timing.
Keith