I'm not a doctor, and the paper is a theoretical research paper. You are on a very minimal dose of NAC, so it is probably not a concern. I was taking like 8x to 10x that much daily.

But my reading of this paper implies that NAC could be an issue for PMR. This may be offset by NAC's positive aspects in your case, but I don't have the expertise to know. I stopped taking NAC for now, but I may start again if it doesn't seem to make a difference.

In my layman's reading of the paper, it says that glutathione removes reactive oxygen species (ROS) generated by the activity of immune system Th17 cells. These are known to be one the primary offenders in PMR. https://pubmed.ncbi.nlm.nih.gov/22833233/

If the ROS species were not removed, this would limit the Th17 attack, and hence logically lessen the PMR symptoms.

If the ROS are removed, the Th17 attack can continue unabated. Since NAC restores glutathione, this implies it helps remove ROS, and could worsen a PMR attack.

Again, I'm not a MD or even a biomedical specialist.