I agree with Lazlo on this one...
I've had it explained before by a knowledgeable chemist before (concerning mainly fresh mushroom honey)
Something bad happens is all I remember, not dangerous but not good. I didn't understand a word.
But IME cracker dry honey, at room temp, in the dark will last for years with no noticeable loss in potency.
I cant say the same for 'fresh mushroom honey' which seems to spoil.