OCI-61716
EMBEDDED_OID key assignment method requires collection content column to be of type JSON. BLOB with OSON (only supported on Autonomous 19c) is also a valid content column type for EMBEDDED_OID.
Cause
EMBEDDED_OID key assignment method was specified with an incompatible content column type.
Action
Ensure that the content column type is JSON, or BLOB (but only on Autonomous 19c database).