I don think this falls under a RFE. moving it to Q&A
@Bill_Demsky can you provide an example of the filter that you are using? I've tested it out on my end and it is functioning as designed. What cluster Version are you on?
Make sure that your time frame is wide enough to include a kubernetes problem. What cluster version are you on? In our instance it is working as designed on the most recent cluster version:
If you are at the most recent version of the Cluster then you might want to open up a support case.
As a work around for the time being I recommend crating a Auto Tag that provides the value of the K8 Cluster to the related hosts, processes and services. This will then allow you to sort problems by tag being "K8 Cluster:<Value>"