Stop in for a cup of coffee

Hello All! Got a call from the powdercoat shop today, bad news, my springs evidently had pads in between the leaves, melted out. I'm kinda thinking if that's what they do that they should have known it was at least possible. Does anyone know if these springs can or should be ran like this?
They powder coated leaf springs assembled? I would assume you would want to do individual leaves or the coating would bond them together and crack when you run them.