What about high vitamin D? Can it be a sign of [a] thyroid issue or usually over-supplementation?

If we’re talking about 25D [calcifediol], which I’m assuming that you are, I don’t think I’ve ever seen a case that wasn’t due to over-supplementation. Yes, the differentiator there is ​125D,​ or calcitriol, can be elevated in a number of conditions that are not related [such as] over-supplementation of vitamin D like calcium deficiency for one. In some cases, [it could be an] autoimmune disease like sarcoidosis and probably others. With that caveat, I would say it’s usually over-supplementation.