That's why I suggested that it would be a wheat intolerance vs a gluten intolerance. Not all Celiacs have issues with these muffins, so either it has be an intolerance to something else or cross-contamination as suggested by another user. There can also be other reasons that have not been discussed yet.
I just wanted to reply to this for visibility. I also had a reaction to these muffins today and I think this is a wheat intolerance vs gluten intolerance. The ingredient "dextrose" is the main culprit for me.