Yes, SAP has completed all and every check before this BTE, error message are no longer expected, so an error message 'E' or 'A' is not managed, and the caller program dump. (Look for OPEN_FI_PERFORM_00001050_E in the FI_DOCUMENT_POST source code, there is no management of any EXCEPTION ERROR_MESSAGE. Other messages don't break the execution flow, so no problem arise.
Regards,
Raymond