CI3 WHERE and ORDER_BY errors

The columns all exist. CI3 was attempting to update the sessions table when it should not have. The core error was mine. If I understand it correctly, CI3 does not use start_cache or flush_cache anymore but instead requires cache_on and cache_off or cache_delete. When I made that change the error is gone. Still leaves me wondering why using the CI2 start_cache in combination with WHERE or ORDER_BY causes CI3 to attempt to update the sessions table with data that is not and does not belong there.