I believe it is an ongoing issue; due to fluoride et al.
Impossible to say when and how much.
I didnt have detox symptoms until I took 10 drops or more of Lugols 5% daily.
I didnt have any fluoride exposure I knew of prior to this, no medication, no chlorinated water.
You say no illness or disease; this is of course very positive, but even if I can say that I too belong to this group; 50-100 mg of Iodine almost daily is my maintenance, vaccination, insurance, proactive etc.