That claim was filed prior to the bankruptcy, had 2 other defendants, and a life of its own once the stay was lifted. While the plaintiffs acknowledged they were not going to get anything from BioAmber (save maybe from its insurer), they still had their claims against the others.
The reason it was settled was the remaining parties in the suit chose to. That has nothing to do with BioAmber's dead status.
The reason the shares are still in your account is because their CUSIP was suspended due to the bankruptcy liquidation, creating the dead company, and the ticker deletion. Sure hope every shareholder understands their stock will never trade again and will lie there in accounts as a reminder of how ridiculous it was to invest in a company that was bankrupt, liquidated, out of business, and deeply in debt, and how listing to the Twitter DD Fabrication Team's fairy tales (about how company's with $100M in debt go through bankruptcy and magically become worth $540M) was a bad investment strategy.
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