The naturopath I took my boys to explained much of it to me, plus I had been reading about naturopathy and homeopathy before making the appt.

It must be the difference in practitioners , as usual there's good and not so good..

Usually the first appt is the most expensive as that is when they ask all the questions to hopefully narrow down to the right remedies..

Have you tried another dose to see if it does the same thing?
Maybe take fewer pellets the next time?

I believe the practitioners buy in bulk and re bottle into smaller containers.

You could also call and tell them what occurred, just so they are aware. Ask if that is normal.
But I really don't think it is, there is such a minute amount of the original ingredient. but it could have been contaminated or mislabeled.
Or he may have bought a bad batch of remedies.