Q&A: Why did my products using Amber Romance type fragrance oil smell like rotten eggs?

In the October Q&A post, Amy asked, So here’s a stinky question! I’ve used Amber Romance (amazing scent) fragrance oil by fragrance buddy, in a batch of shampoo bars and a lotion bars, and a few days later they started smelling like rotten eggs ?. WHY?? Maybe because they’re heated? I haven’t had any other fragrances do…