Recurring SqlExecutionException

When analyzing very big maven log file in our CI system, I found out that there is a recurring SqlException (subset of the log file is attached):

 
org.apache.flink.table.gateway.service.utils.SqlExecutionException: Only 'INSERT/CREATE TABLE AS' statement is allowed in Statement Set or use 'END' statement to submit Statement Set.
 
 

which leads to:

 
06:31:41,155 [flink-rest-server-netty-worker-thread-22] ERROR org.apache.flink.table.gateway.rest.handler.statement.FetchResultsHandler [] - Unhandled exception.