Hi Martin,
FYI there is NO issue with the DB2 CK driver - its doing what its suppose to do.
The CK driver is only fetching columns below 1M (as per JIT threshold) based on SQL statement logs
My suspect could be the DD, as it tries to update its buffers/pointers - I'm not sure if the internal working of the DD actual retrieves the BLOB OnNewCurrentRecord or waits until its used to retrieve it.