Same issue here, filed as FB24150787. Two iOS devices (iPad Air 5th gen, iPhone 17 Pro, both 26.5.2), ADP enabled: every export fails with RecordSave → BAD_REQUEST, returnedRecordTypes _pcs_data, in com.apple.coredata.cloudkit.zone. Import still works. Device reboots and toggling the app's iCloud switch do not help. Interesting data point: the same app/account on a Mac whose sync state was set up fresh after the wedge exports fine — and CloudKit Console shows an unrelated user of our app with the exact same failure signature. So this looks account/PCS-side, not app-side. The device-side PCS identity is valid per pcsstatus.txt, pointing to a server-side inconsistency in the zone's _pcs_data manifest.