Unknown service envoy.service.discovery.v3.AggregatedDiscoveryService

I am trying to install Istio v1.10.2 with ipV6 in air gapped environment. After doing a operator based install with demo profile, I see the ingressgateway struck at readiness probe, and logs having warnings like

2021-07-08T08:14:22.299526Z info xdsproxy connected to upstream XDS server: istiod.rcp-istio-system.svc:15012
2021-07-08T08:14:22.300445Z warn xdsproxy upstream terminated with unexpected error rpc error: code = Unimplemented desc = unknown service envoy.service.discovery.v3.AggregatedDiscoveryService
2021-07-08T08:14:22.303598Z warning envoy config StreamAggregatedResources gRPC config stream closed: 12, unknown service envoy.service.discovery.v3.AggregatedDiscoveryService
2021-07-08T08:14:22.317779Z info cache generated new workload certificate latency=4.983839281s ttl=23h59m59.682292793s
2021-07-08T08:14:22.317899Z info cache Root cert has changed, start rotating root cert
2021-07-08T08:14:22.317934Z info ads XDS: Incremental Pushing:0 ConnectedEndpoints:0 Version:
2021-07-08T08:14:22.318003Z info cache returned workload trust anchor from cache ttl=23h59m59.682002872s
2021-07-08T08:14:22.532949Z info xdsproxy connected to upstream XDS server: istiod.rcp-istio-system.svc:15012
2021-07-08T08:14:22.536083Z warn xdsproxy upstream terminated with unexpected error rpc error: code = Unimplemented desc = unknown service envoy.service.discovery.v3.AggregatedDiscoveryService
2021-07-08T08:14:22.536594Z warning envoy config StreamAggregatedResources gRPC config stream closed: 12, unknown service envoy.service.discovery.v3.AggregatedDiscoveryService

I see that istiod constantly throwing transport closing logs once ingressgateway comes up

Any clue on what’s wrong ?

-Kamesh