This was a problem fixed in 3.11.1 (CASSANDRA-13641 <https://issues.apache.org/jira/browse/CASSANDRA-13641>). You might have lots of old prepared statements in there that didn't get cleared out so truncating should probably fix it for you.
- QueryProcessor.java:160 - prepared statement recreation ... Ridley Submission
- Re: QueryProcessor.java:160 - prepared statement re... kurt greaves