The reference is, I believe, to an amendment inserted by Senator Corker to the 2016 spending bill passed last December to avoid another government shutdown. By recollection it banned any action being taken by government until 2018. I have a link for it on my other computer which is not with me at the moment.
There was a timeline on the omnibus bill. It said they couldn't be sold for a certain period. I want to say 2 years from the passing of the bill. I will have to research.
However, the court could invalidate the warrants without congressional approval. The bill only states the Treasury/FHFA/conservator could not sell the warrants.
Plus, any action by Congress could always be overturned in the courts. That is part of the checks and balances.