Key TakeawaysShares of Instacart, trading under the name of its parent, Maplebear, tumbled Wednesday, after the grocery delivery service issued soft guidance, noting that one of its partners was hit with an internet outage.The grocery delivery firm said the problem affected deliveries for grocers operated by Ahold Delhaize. Instacart beat profit and sales estimates in the third quarter, and turned profitable. It also raised its stock buyback program. Shares of Instacart, trading under the name of its parent ...