Tech Trading Bug?

I've had the Krynn offer me "Counterespionage" for trade but the trade screen is blank where the tech should be listed. In my experience, if one trades for that, he or she will get nothing despite the fact that Counterespionage appears in his or her tech tree (I was playing Terrans). Is this intended? Do the Krynn have some special counterespionage tech that other players don't and can't have access to? If so, shouldn't the Krynn be prevented from even offering it for trade in the first place?

I've also done this in the opposite direction. One AI race (do not recall which one)desperately wanted one of my unique techs (don't remember which one). I gladly made the trade it offered and acquired a tech I was after. Despite that, it appeared the AI never got my unique tech because it came back repeatedly trying to trade for that tech in latet turns. Only after this happened a few times and I had acquired several techs did I realize this and thereafter stopped trading for that tech (because in my opinion it was an unfair player exploitation).