E2E tests fixes

modules/net-vpc/subnets.tf

@@ -182,6 +182,12 @@ resource "google_compute_subnetwork" "proxy_only" {
   )
   purpose = each.value.global ? "GLOBAL_MANAGED_PROXY" : "REGIONAL_MANAGED_PROXY"
   role    = each.value.active ? "ACTIVE" : "BACKUP"
+
+  lifecycle {
+    # Until https://github.com/hashicorp/terraform-provider-google/issues/16804 is fixed
+    # ignore permadiff in ipv6_access_type for proxy_only subnets
+    ignore_changes = [ipv6_access_type]
+  }
 }
 
 resource "google_compute_subnetwork" "psc" {