Yes, especially if the thin 'weed fabric' version of membrane was used, the one commonly available at garden centres by the roll. There are thicker geotextile fabrics available through which the grass might not have penetrated, but its always best to remove turf before laying membrane and stones.

Agree totally with Bamboo, turf needs removing first!

Give it a good dose of Roundup now. Then another one in the Spring.

Won't stop the grass from continuing to come through and Roundup does remain in the soil, in spite of what the manufacturers say.