A call to setSeedNamespace will potentially reorder the contents of the input slice, interfering with other potential uses.  Since this is populated with the contents of the service mesh member roll .status.configuredMembers list it may interfere with other references.

The particular conflict which brought this to light involved updates sent to the MultiNamespaceListerWatcher as, in the right conditions, it resulted in a namespace being duplicated within the list.

The result of this conflict would be repeated error messages in the pilot log such as

error   k8s.io/client-go@v0.18.3/tools/cache/reflector.go:126: Failed to list *crd.IstioNetworkingV1Alpha3Envoyfilters: envoyfilters.networking.istio.io is forbidden: User "system:serviceaccount:istio-system-v2:istiod-service-account-testsmcp-v2" cannot list resource "envoyfilters" in API group "networking.istio.io" in the namespace "test-99"