What a gr8!! question.. lol and guess it (shelf) is a bit uneven, I never noticed that. This would also explain why it’s not happening to everyone of the dishes. I’m alternating shellfs in order to produce faster…lol one comes out a new one goes in. My temp is 1350 also. I have been baffled as to how it could “burn” one side and only sometimes . gonna see how it does once I level the shelf better.
I will write again to let the progress shine from here… Thank you for your thought.