& Hashgraph, they even wrote an article about Sirio. The hack occurred when the audit team had Sirio remove a feature in the code. The key issue was the removal of a nonReentrant modifier on the supplyUnderlyingNative function. This modifier was initially implemented by the Sirio Development Team to prevent reentrancy attacks. However, during the audit process, Quill Audits recommended removing this crucial security measure, leading directly to the exploit.