rubbery potatoes? How does that happen?

I’m not talking about soft raw potatoes. I’m talking about some roasted potatoes cut into roughly half inch widths. I got roasted potatoes at a food truck, and good them home about 15 minutes later. They tasted rubbery, or maybe spongy (not leathery) in a way I hadn’t experienced either cooking myself or eating out. Does anyone know how that could happen?