In the DX SAAS UI under:
Triage -> Topology Map: it is missing UMA clusters for K8s Cluster type. Presently it is only showing one cluster. There should be around 6 UMA clusters that should be showing in the APM UI. These 6 UMA clusters are reporting metrics good under Metrics/Traces By Agent. This is also causing issue with missing cluster data in the out of the box dashboard (UMA Cluster Information) due to incomplete Topology Map data for UMA agent.
Restarted container monitor POD in the UMA agent cluster, which restored missing topology data and resolved the issue with out of the box dashboard (UMA Cluster Information).