Whether a United States Court of Appeals can sua sponte affirm a district court's judgment on Rule 9(b) and other grounds that were waived on appeal without giving the appellants an opportunity to amend their complaint

Whether a United States Court of Appeals can— sua sponte —affirm a district court’s judgment on Rule 9(b) and other grounds that neither the parties nor the district court ever addressed below or in the parties’ appellate briefing and, as a result, were waived on appeal, especially when the appellants had no opportunity to amend their complaint.