Do you talk about the fact that a research, available for a type of civ and unavailable to a non-carbon life (ex.: synthetics) is proposed over and over again ?
I think I saw this thread not far down in the forum, and yes, a dev said that it was registered in the bug-tracking internal system, in the pipe for next patch.
I mostly play a synthetic customized civ. And I can confirm that this issue still exists (images are extracted this morning from my current game): If I was playing a carbon base civ (needing food and entertainments), I would try to find a silicate or synthetic civ for always selling the same useless research!
You know that a Tech proposed for trading is part of your research tree if there is an estimated research time (a number, or N/A if you just restart a game):
Now, you know that this research is NOT for you when there is nothing estimated, and it is totally blank :
In theory, this tech should NOT appear in the trading menu proposed to you...
In this case, as a synthetic life, I can buy this "Xeno Entertainment" tech, and next time I can trade again with this civ, it will be there (I have spent money for nothing).
If it is an AI, they can propose it over and over in trades, or offering it for declaring war on another civ... Endless business.
As I know the trick (I check for the estimated time), and play synthetic versus the AI, no big issue. But it is really an exploit if used the other way around.
By the way : when starting a new game, always disable the trade brokering. I find this default setting abnormal, and game breaking as, especially at highest levels and Godlike, all civs (but you) knows it all before the 100th turn ! ...
Other downside of the trade brokering : as, in tech brokering, the useless techs will be offered by the AI to the AI, and they behave like robots/ados ("I want this tech!" - "but you cant have it..." - "I don't care, I want this tech !!"), you see that silicate and synth civs will always try to trade/buy something they can't use, and as it is proposed , they try - like good robots - to have it a again until they are broke ! And even broke, they trade with negative numbers for credits !! (I saw this in Godlike, not other levels).