# UNDF: UNDF-2026-000000742
# UNDF: (leave blank)
--- a/xds/src/main/java/io/grpc/xds/PriorityLoadBalancer.java
+++ b/xds/src/main/java/io/grpc/xds/PriorityLoadBalancer.java
@@ -65,7 +65,7 @@ final class PriorityLoadBalancer extends LoadBalancer {
   private ResolvedAddresses resolvedAddresses;
   // List of priority names in order.
   private List<String> priorityNames;
+  private Set<String> priorityNamesSet = new HashSet<>();
   // Config for each priority.
   private Map<String, PriorityChildConfig> priorityConfigs;

@@ -89,6 +89,7 @@ final class PriorityLoadBalancer extends LoadBalancer {
     checkNotNull(config, "missing priority lb config");
     priorityNames = config.priorities;
+    priorityNamesSet = new HashSet<>(config.priorities);
     priorityConfigs = config.childConfigs;
     Status status = Status.OK;
-    Set<String> prioritySet = new HashSet<>(config.priorities);
+    Set<String> prioritySet = priorityNamesSet;
     ArrayList<String> childKeys = new ArrayList<>(children.keySet());
     for (String priority : childKeys) {
       if (!prioritySet.contains(priority)) {
@@ -122,7 +126,7 @@ final class PriorityLoadBalancer extends LoadBalancer {
     Collection<ChildLbState> childValues = new ArrayList<>(children.values());
     for (ChildLbState child : childValues) {
-      if (priorityNames.contains(child.priority)) {
+      if (priorityNamesSet.contains(child.priority)) {
         child.lb.handleNameResolutionError(error);
         gotoTransientFailure = false;
       }