Welcome to the forum.
If the smoker hasn't been used for some time. it may have some moisture in the element that can cause the GFI to trip. After running for a while, try the GFI again and it may not trip.
I just cook my ribs without doing anything except smoking for about 4 hours then wrapping in foil and putting some butter and brown surgar/honey mix to baste ribs until done around 5 hours total.