It seems, the source table has a column which doesn't exist in the target table.
That is , replicat tried to apply a record by using a specific key from the source table, but some or all of the matching key columns do not exist in the target table.
IF you want to omit the replication of XML columns, you may use COLSEXCEPT.
Read the following for the supported data types:
18c (18.1.0)
E95983-04
January 2019
https://docs.oracle.com/en/middleware/goldengate/core/18.1/oracle-db/using-oracle-goldengate-oracle-database.pdf - "section - Understanding What’s Supported"