In past instances when I have seen this, the version of access server and MC were older than when the KCOP feature was introduced to the Kafka target. Essentially the management console is on a version that does not realize User Exits for KCOPs are a valid option.
It's unlikely the issue but you'll also want to confirm the actual version of your IDR Kafka target by considering the additional version level information. It should be something like this... IDR 11.4.0.3-5566.
For reference, A link to release notes is here (showing latest version of the IDR Engine code etc). https://www.ibm.com/support/pages/release-notes-iidr-114-replication-engines-linux-unix-and-windows
I would try moving up to a recent version of MC and access server and recreate the subscription (just for thoroughness but most likely not necessary).
If this doesn't resolve the issue, IBM's support tickets will definitely be able to help.
(I'm the owner of the IBM IDR Kafka target in development).
Cheers.