My Daughter Often Has A Burnt Popcorn Taste In Her

My daughter often has a burnt popcorn taste in her mouth...it makes her nauseated. Can you help me understand? No fever is ever present and it is usually (not always) followed by vomiting...doesn't continue for very long after regurgitation Thank you so much She's 12 she sometimes complains of the rotten egg taste that everyone associates with gallbladder issues