I received the following statement in the logs:

Caused by: io.debezium.text.ParsingException: DDL statement couldn't be parsed. Please open a Jira issue with the statement 'ALTER TABLE MYSCHEMA.MY_PLANT DROP PRIMARY KEY DROP INDEX;'

extraneous input 'INDEX' expecting {'DISABLE', 'ENABLE', ';'}

This occurred in Oracle 11.2.0.4