Same issue here with macOS 27.2 (26B123, release) and Xcode 27.1 (27A9275), affecting both iOS (ITMS-90035) and macOS (ITMS-90238). The designated requirement embedded by Xcode contains the NFD bytes 61 cc 88 for “ä”, while the certificate stores NFC c3 a4. Root cause appears to be NSTask/Process decomposing the --requirements argument to NFD. Filed as FB25351765 with a minimal repro.