Post error “Unexpected Oracle error: ORA-01400: cannot insert NULL into” in CDC environment (4301200)

Post stops as below in a  CDC environment:

Error    2016-01-25 11:09:52.345564 13340 310298368 s:3 Poster: que/seq = 3/ 83872 seqno/offset = 6703/124989060 Unexpected Oracle error: ORA-01400: cannot insert NULL into ("OWNER"."TABLE_NAME"."COLUMN_NAME"). (object name:"OWNER"."TABLE_NAME") (posting from SID1, queue queue_name, to SID2) [module opo]

The column named COLUMN_NAME has NOT NULL constraint defined on both source and target database.

The config file  is using user defined key to include all columns in the table, something like:

OWNER.SOURCE_TABLE  !key (COLUMN1, COLUMN2, …..)  !cdc:OWNER.TARGET_TABLE  target_server@c.targetSID

The above is done to bring over all columns in the WHERE clause to the target.