So many reasons to say, “It depends.” The thickness of the
cardboard, the prolonged wetness of the cardboard, the thickness of the organic matter above the cardboard, and the length of time the cardboard had to decompose before the roots try to grow.
I would poke at the cardboard at the time of planting. If there was a lot of resistance, I’d cut or poke a hole in the cardboard at the time of planting.
Best of luck with that garden!