I found a convincing answer here connected to delays in raising the debt ceiling among other things like corporate tax payments in Sep. https://www.ibtimes.com

I found a convincing answer here connected to delays in raising the debt ceiling among other things like corporate tax payments in Sep. https://www.ibtimes.com/new-york-fed-steps-market-move-interest-rates-2828111 https://www.ibtimes.com/new-york-fed-steps-market-move-inter...