Care to explain your observation? I think we could assemble a little list of possible visual cues.
My guesses: visually defenders get a bit "wiggly" in front of their challenger when they are trying to force counter, especially when high pressing.
Defenders shift more often into open passing lanes and further from defenders, or are more willing to double team when zonal.
I think there are also attack patterns that happen mostly when off-side trap is broken.