I tried an experiment with not letting the dough proof in the pan as long to see what would happen. After the dough ball was opened and placed in the steel pan with the metal lid on, I placed the tray on the top of my oven for ½ hr. I usually let the dough proof in the pan for an hour or more on the top of my oven.
The resulting pizza had a gum line. I am not sure if the gum line came from not proofing the dough long enough, but it appeared to me that is what caused the gum line. The slices still tasted the same, but I sure don’t want a gum line.