That was a bug in Optimism not Ethereum. No funds on Ethereum were at risk. Optimism is a separate project which runs a separate layer 2 network that helps run

That was a bug in Optimism not Ethereum. No funds on Ethereum were at risk. Optimism is a separate project which runs a separate layer 2 network that helps run blockchain transactions faster. It uses Ethereum as its data store but is separate in most other ways.