I know there is a term for cases where two mathematical propositions are equivalent but only one is intuitive and the other (and thus the equivalence) is not. Also, the term might apply to surprising, unintuitive connections across different subfields. I believe the term was coined by a mathematician, possibly in the context of category theory, reverse mathematics, mathematicaal foundations, and/or the equivalency of Zorn's lemma and Axiom of Choice. I believe the term is a adjective/noun phrase.
Any help is greatly appreciated. I have scoured my search history for it. It is driving me crazy.
Maybe it's the word cryptomorphic that you're looking for?