This was a common bug in the Civ 5 trainer. Just reactivate the option and switch what you are researching. Doing so should fix things. You might need to press the option more than once and bounce to a few different researches.
First off, great trainer. I am not usually into Sims like this, but now I am having some fun with it.
But I did want to ask about the food option. So far everything else has worked, but I just can't seem to get the food option to work. I have tried clicking on the city first then using the option, as well as clicking first then clicking the city. There is probably a trick to it...so anyone having success with it? And if so, what are you doing?