Tried 2 pita balls on the stove, one rolled very flat, did not puff, the other not as flat: didn't puff and burned. \What should I try next

I have a question about step 9 on the recipe "Pita Bread" from lapadia. It says:

"Alternate pita baking would be to place the dough on a baking sheet, it works great, you can make 3-4 at the same time, this is actually my favorite way to bake them. Bake for 5 to 7 minutes, until lightly browned and puffed. My oven takes between 6.5 to 7 minutes, they start to puff a little over 3 minutes."