diff --git a/.github/workflows/RunUnityTests.yml b/.github/workflows/RunUnityTests.yml
index 8d469bac2..44911ff96 100644
--- a/.github/workflows/RunUnityTests.yml
+++ b/.github/workflows/RunUnityTests.yml
@@ -14,7 +14,7 @@ jobs:
           - 2019.4.40f1
           - 2020.3.44f1
           - 2021.3.18f1
-          - 2022.2.5f1
+          - 2022.2.6f1
 
     steps:
       - name: Checkout repository
diff --git a/Assets/Mirror/Core/Tools/Extensions.cs b/Assets/Mirror/Core/Tools/Extensions.cs
index 345e17b98..28c91e560 100644
--- a/Assets/Mirror/Core/Tools/Extensions.cs
+++ b/Assets/Mirror/Core/Tools/Extensions.cs
@@ -9,7 +9,11 @@ public static class Extensions
         public static string ToHexString(this ArraySegment<byte> segment) =>
             BitConverter.ToString(segment.Array, segment.Offset, segment.Count);
 
-        public static readonly Dictionary<string, int> StableHashes = new Dictionary<string, int>();
+        // GetStableHashCode is O(N).
+        // the longer the string, the more it needs to compute:
+        // https://github.com/MirrorNetworking/Mirror/pull/3377
+        // cache results for O(1) lookups.
+        static readonly Dictionary<string, int> StableHashes = new Dictionary<string, int>();
 
         [UnityEngine.RuntimeInitializeOnLoadMethod]
         public static void ResetStatics()