I am type two, and my thyroid failed some time ago.
When diagnosed my TSH was four thousand times higher than the top of normal.
I had been complaining of the symptoms for years, but the tests did not show any problem, just lowish levels, so the GPs would not order any more tests, then a new one arrived at the practice and saw me when I took one of the children to the surgery, ordered tests and I started Thyroxine the next week.
Thyroid hormones regular a lot of things around the body - and they fluctuate for a long time before eventual failure, I discovered, so it would be possible for the changes to be ongoing and long term for all sorts of things.