Local Dunkin smells like burnt something, even in the food taste.....

We've noticed the last 2-3 months our local Dunkin always smells like something has almost plastic/chemical has burnt when you walk in, it's even in the taste of the cooked food/sandwiches etc. yet the food itself has not been burnt. First time we thought someone just burnt the heck out of something, but it's been that way every time we've gone in there since. We've stopped going there but have always wondered what could be causing it. I've read other places that if they don't change the oven liners enough there can be a bad smell/taste. It's almost like a burnt/gas smell like something off a charcoal grill if you don't let the lighter fluid burn off enough before you start cooking.