CAMT053 Bank statement load failing with CE-660228 Despite custom JPM Format

Summary:

We are trying to load JPMorgan chase CAMT053.001.02 bank statement files into oracle fusion CM using the Load and import bank statement ESS process. The file contains statement for 6 bank accounts(5 USD and 1 GBP)

Before raising this post we have verified the below:

XML namespace: urn:iso:std:iso:20022:tech:xsd:camt.053.001.02
Root element: <Document> → <BkToCstmrStmt> → <Stmt> (no AppHdr wrapper)
Balance dates use <Dt> not <DtTm>
File is zipped before uploading to UCM
File uploaded to UCM account: fin/cashManagement/import
File is being read by the system (log shows respPayload.available() = 14903)

Oracle Setup:
Banks and branches exist with correct BIC codes