USM was attacked, resulting in a loss of approximately 70.83 ETH

The pricing logic in the ethFromDefund() redemption function of the USM contract defund() has flaws. This function calculates the consideration for a single redemption using the arithmetic average of the current FUM selling price and the estimated terminal FUM selling price, but this algorithm lacks split invariance.

After adding the state contraction coefficient adjShrinkFactor associated with a single redemption and the integer rounding mechanism, the total amount of Ethereum that can be extracted from splitting an equal amount of FUM assets into 64 small redemption operations will be significantly higher than that obtained from a one-time large redemption.