The fridge in my coleman popup is "popping" when the burner is lit. When it pops, the flame shoots any open space around the burner.
Has anyone else been through this? Any ideas how to resolve this?

Have you checked the air intake to the burner for any obstruction (i.e. spider webs)? These can restrict air to the burner and cause "poping" when igniting and a yellow flame (the flame should be blue) when lit.

Thanks. I'll check that. Flame is yellow.

With a yellow flame you have a air supply problem. Check the burner tube for obstructions, and clean orifice, or for a couple dollars jst replace it.