My daughter had bronchitis pretty bad twice since we started vaping. Not bad enough to be hospitalized, but bad enough to miss a week's work each time. She had gotten bronchitis several times while we were smoking, before we quit and started vaping. Both times since vaping she was using a cinnamon-heavy eliquid. One was a Snickerdoodle flavor that she loved, from a vendor that we had been using since we started vaping. I can't remember right now what the other one was, but it was from a different vendor. Again, she really liked the flavor. It could just be coincidence, but it is strange that both times she got sick since we have been in California, she was vaping cinnamon-centered eliquid. My personal take on it is that she got run down due to stress and workload, and the cinnamon-centered eliquid was the last straw. We both have allergies, and she is gluten-sensitive, so I am of the opinion that sensitivities come into play somewhere.
She has not had any problems recently, but, then again, I am very careful about what I order for her. When we are trying a new vendor, I tend to avoid cinnamon-heavy eliquids when I am getting something for her to try. Once we have ordered a couple of times, I lay down the law, and tell her to check the website so she can let me know what she wants, instead of me trying to guess what she might enjoy.
Did you change anything else before you got sick? Flavorings, recipe tweaks, new equipment, etc.?