I’m unsure if it’s unsafe. The kernals are safe at room temperature, but once they’ve been heated, they could become unsafe?
Surprisingly, my food manager safety test did not cover this.
It did cover to never touch turtles then food.
My main concern would be the kernals might simply not want to pop, either from being stale or the previous heating process made the water inside escape but not explode the kernal, so there’s no more left to make it explode now.
Gunna have to warm my mother who lives to knit but is deadly allergic to shellfish to be careful of yarn, I think??