This is notable because the change in perceived risk (as measured by the yield) of default appears greater in the shorter term government debt (1mo) as compared to the debt maturing later (3mo). It would indicate that "the market" believes there may be some technical non payment scenario over the short term (so, government shutdown related), but there appears to be no fear-mongery shaking of the faith in the nation. As you can see in the link the 30yr bond's yield has in fact fallen over the same period.

As this is a technical crowd, and there are requests for layman explanations, I'll elaborate some: Yield = Interest rate. This is inverse to the price of the bond. If you hold a bond and the yield rises (say, from 10bps to 27bps), you have lost money on your holding since the market price fell. The unexpected yield increase (price fall) on short term treasuries is notable because short term government bonds are held in large quantity by very risk averse investors (e.g. money market accounts) that not expecting to take losses. The unlikely downside scenario of a one off non-payment or deferred payment may cause settlement problems in short-term bond markets, or even a "freeze" as happened after Lehman collapsed.

Typically the yield of a bond increases over longer maturities because there is more time for something to potentially go wrong leading to an inability to pay. Thankfully, the United States is a sovereign nation that prints its money on keyboards, so that is only possible if a decision not to pay is made.