Istio 1.8.2 Multi-cluster with headless/mongodb

I have a multi-cluster set up with multiple primaries and different networks.

The setup and verification works. I have setup 3 statefulset mongo nodes on one cluster and 2 on the other.

I want to form 1 replica set out of these nodes.

I can’t get cluster1 mongo nodes to talk to cluster2

I have sidecar injection on and I can form a replica set with just cluster1.

Any ideas? Any pointers on debugging?