I've been feeding crickets to my dragons as a staple feeder insect for nearly 9 years , never had issues with GIT paracites with my dragons or skinks.
I think the risk of feeder insects who have been breed / farmed under properly sanity/clean conditions giving the reptiles who they are fed to GIT paracites is very overstated and exaggerated.
I'd be looking closely at the food you are feeding to the crickets and ensuring it's been washed before they get it, same reason why we wash our salad and veg before eating it.