I'm experiencing the same problem in Firefox 134.0 (aarch64) on macOS 14.6.1 (Apple M1). Console 1.1, shows these messages when connected to my iPhone 14 running iOS 18.1.1: error 14:43:31.069080+0000 PassbookUIService Codable: Failed to decode Merchant Session Created: Error Domain=NSCocoaErrorDomain Code=4864 UserInfo={NSCodingPath=<private>, NSDebugDescription=<private>} error 14:43:31.069103+0000 PassbookUIService Session 12311: Fatal Error: Failed to decode merchant session created

After installing the Apple Pay for iOS profile, the log messages from Console are more detailed: error 13:38:31.786791+0000 PassbookUIService Codable: Failed to decode Merchant Session Created: Swift.DecodingError.typeMismatch(Swift.UInt, Swift.DecodingError.Context(codingPath: [CodingKeys(stringValue: "messageBody", intValue: nil), CodingKeys(stringValue: "updateBody", intValue: nil), CodingKeys(stringValue: "merchantSession", intValue: nil), CodingKeys(stringValue: "epochTimestamp", intValue: nil)], debugDescription: "Expected to decode UInt but found a string instead.", underlyingError: nil)) error 13:38:31.786824+0000 PassbookUIService Session 11150: Fatal Error: Failed to decode merchant session created I've submitted FB16392549.