Normally, when evaluating technologies to ask for or offer when trading with another civilization, the game displays the number of months it would take to research the technology to the right of the name of the technology.  The first screen snapshot below is from a trade offer that was initiated by the Onyx Hive and shows the expected behavior in the popup window that appears when I hover over the Advanced Composites technology that they are offering. However, the second screen snapshot from the same trade windows shows that, when I hover over one of the technologies that they want from me, the game does not display the number of months it would take to research the technology. This same issue occurs when I hover over any of the technologies that I have in my "Techs" list while hovering over any of the other civilization's technologies works as expected.

However, if I initiate a trade offer, the number of months it would take to research the technology appears for both my technologies and their technologies as expected.  Therefore, I think the bug has something to do with an AI initiated trade offer.