Discovery "Cache appears to be missing latest version of networking.istio.io/v1alpha3/"

Hi team,

We have just upgraded from v1.7.7 to 1.8.5, via 1.8.4 using a canary deployment. Both the 1.8.4 and 1.8.5 are manifesting the behaviour described below.

The system itself is working, but the istiod pods are belting out these warnings, for all configured network rules.

istiod-1-8-4-6dc6bcc7cb-8wr4j discovery 2021-04-19T01:53:40.901314Z     warn    status  Cache appears to be missing latest version of networking.istio.io/v1alpha3/virtualservices/egress/vs1/352180251
istiod-1-8-4-6dc6bcc7cb-8wr4j discovery 2021-04-19T01:53:40.901344Z     warn    status  Cache appears to be missing latest version of networking.istio.io/v1alpha3/destinationrules/egress/dr1/352182191

The ingress and egress proxies are in separate namespaces from istiod.

All the istio network policies are configured using the v1beta1 api and there is nothing I can see (have found) referencing the alpha api.

API Version:  networking.istio.io/v1beta1
Kind:         DestinationRule
Metadata:
  Generation:          1
  Resource Version:    352182191
  Self Link:           /apis/networking.istio.io/v1beta1/namespaces/egress/destinationrules/dr1

The message is coming from here -istio/reporter.go at 4d6e76c457a653329aae2aabeb2a5a694484b478 · istio/istio · GitHub - I guess, but I’m hoping someone here can explain the cause and probable fix

Thanks.