Yes, glutathione can make a person herx. From my understanding it's because it flushes toxins out - and if the detox pathways of the body get overloaded, those toxins will circulate in the blood and be redeposited elsewhere in the body.
We have had several posts from those that have herxed on glutathione lately.
This article helps to explain what's going on:
www.tiredoflyme.com/4-reasons-why-you-still-feel-bad-despite-detoxing.html - scroll down to #2