Indeed, Lots Of Propping Going On.

http://investmentresearchdynamics.com/a-liquidity-crisis-hit-the-banking…
Something occurred in the banking system in September that required a massive reverse repo operation in order to force the largest ever Treasury collateral injection into the repo market.   Ordinarily the Fed might engage in routine reverse repos as a means of managing the Fed funds rate.   However, as you can see from the graph below, there have been sudden spikes up in the amount of reverse repos that tend to correspond the some kind of crisis – the obvious one being the de facto collapse of the financial system in 2008:

……..