I think the stuff about redistribution of heavy metals above is somewhat hyperbole and misunderstood, not least since it relates to all 'detoxification' agents, not just NAC. Y'all might find this review helpful:
Chelation: Harnessing and Enhancing Heavy Metal Detoxification—A Review - PMC
Toxic metals such as arsenic, cadmium, lead, and mercury are ubiquitous, have no beneficial role in human homeostasis, and contribute to noncommunicable chronic diseases. While novel drug targets for chronic disease are eagerly sought, potentially ...www.ncbi.nlm.nih.gov
So, it seems that this is saying chelation agents more commonly act within internal tissues more readily, often binding to heavy metals for excretion—particularly if the Chelator is water soluble.
Fat soluble Chelators pose greater risk of Redistributing toxins because they are excreted through bile.
it seems to be saying NAC is generally safe and doesn’t cause redistribution.
Did I understand that correctly?