diff --git a/src/benchmarks/micro/libraries/System.Collections/Frozen/Perf_FrozenDictionary_String.cs b/src/benchmarks/micro/libraries/System.Collections/Frozen/Perf_FrozenDictionary_String.cs
index 137792b2197..76cd74096f4 100644
--- a/src/benchmarks/micro/libraries/System.Collections/Frozen/Perf_FrozenDictionary_String.cs
+++ b/src/benchmarks/micro/libraries/System.Collections/Frozen/Perf_FrozenDictionary_String.cs
@@ -13,7 +13,7 @@ namespace System.Collections
     [BenchmarkCategory(Categories.ThirdParty)]
     public abstract class Perf_FrozenDictionary_String
     {
-        protected string[] _array;
+        protected string[] _array, _notFound;
         protected Dictionary<string, string> _dictionary;
         protected ImmutableDictionary<string, string> _immutableDictionary;
         protected FrozenDictionary<string, string> _frozenDictionary;
@@ -65,12 +65,27 @@ public bool TryGetValue_True_FrozenDictionary()
             return result;
         }
 
-        protected void EnsureRightStrategyIsUsed(string name)
+        [Benchmark]
+        [BenchmarkCategory(Categories.Libraries)]
+        public bool TryGetValue_False_FrozenDictionary()
+        {
+            bool result = default;
+            var collection = _frozenDictionary;
+            string[] notFound = _notFound;
+            for (int i = 0; i < notFound.Length; i++)
+                result ^= collection.TryGetValue(notFound[i], out _);
+            return result;
+        }
+
+        protected void Verify(string name)
         {
             if (!_frozenDictionary.GetType().Name.Contains(name))
             {
-                // commented out until https://github.com/dotnet/runtime/pull/87988 gets propagated to installer
-                // throw new InvalidOperationException($"Either we are using wrong strategy ({_frozenDictionary.GetType().Name}), or the type has been renamed.");
+                throw new InvalidOperationException($"Either we are using wrong strategy ({_frozenDictionary.GetType().Name}), or the type has been renamed.");
+            }
+            else if (_array.Length != _notFound.Length || _array.Any(text => _notFound.Contains(text)))
+            {
+                throw new InvalidOperationException("Invalid state");
             }
         }
     }
@@ -90,14 +105,16 @@ public override void Setup()
                 throw new ArgumentException($"{nameof(Count)} needs to be a multiply of {nameof(ItemsPerBucket)}");
             }
 
-            _array = Enumerable.Range(1, Count / ItemsPerBucket)
+            string[] all = Enumerable.Range(1, Count * 2 / ItemsPerBucket)
                 .SelectMany(length => Enumerable.Range('a', ItemsPerBucket).Select(character => new string((char)character, length)))
                 .ToArray();
+            _array = all.Take(Count).ToArray();
+            _notFound = all.Skip(Count).ToArray();
             _dictionary = _array.ToDictionary(item => item, item => item);
             _immutableDictionary = _dictionary.ToImmutableDictionary();
             _frozenDictionary = _dictionary.ToFrozenDictionary();
 
-            EnsureRightStrategyIsUsed("LengthBucketsFrozenDictionary");
+            Verify("LengthBucketsFrozenDictionary");
         }
     }
 
@@ -108,14 +125,16 @@ public class Perf_SingleCharFrozenDictionary : Perf_FrozenDictionary_String
 
         public override void Setup()
         {
-            _array = Enumerable.Range(char.MinValue, Count)
+            string[] all = Enumerable.Range(char.MinValue, Count * 2)
                 .Select(character => new string((char)character, 10))
                 .ToArray();
+            _array = all.Take(Count).ToArray();
+            _notFound = all.Skip(Count).ToArray();
             _dictionary = _array.ToDictionary(item => item, item => item);
             _immutableDictionary = _dictionary.ToImmutableDictionary();
             _frozenDictionary = _dictionary.ToFrozenDictionary();
 
-            EnsureRightStrategyIsUsed("SingleChar");
+            Verify("SingleChar");
         }
     }
 
@@ -137,18 +156,20 @@ public override void Setup()
             // bcbbbbbb
             // bdbbbbbb
             // so the first char is not unique, but the combination of 1st and 2nd is.
-            _array = Enumerable.Range(char.MinValue, Count / 2)
+            string[] all = Enumerable.Range(char.MinValue, Count)
                 .SelectMany(character => new string[]
                 {
                     $"{(char)character}{(char)(character+1)}{new string((char)character, 8)}",
                     $"{(char)character}{(char)(character+2)}{new string((char)character, 8)}"
                 })
                 .ToArray();
+            _array = all.Take(Count).ToArray();
+            _notFound = all.Skip(Count).ToArray();
             _dictionary = _array.ToDictionary(item => item, item => item);
             _immutableDictionary = _dictionary.ToImmutableDictionary();
             _frozenDictionary = _dictionary.ToFrozenDictionary();
 
-            EnsureRightStrategyIsUsed("Substring");
+            Verify("Substring");
         }
     }
 
@@ -159,16 +180,17 @@ public class Perf_DefaultFrozenDictionary : Perf_FrozenDictionary_String
 
         public override void Setup()
         {
-            _array = Count == 10
+            string[] all = Count == 10
                 // to avoid using LengthBucketsFrozenDictionary we specify the same length for more than 5 strings
-                ? ValuesGenerator.ArrayOfUniqueStrings(10, minLength: 25, maxLength: 25)
-                : ValuesGenerator.ArrayOfUniqueValues<string>(Count);
-
+                ? ValuesGenerator.ArrayOfUniqueStrings(10 * 2, minLength: 25, maxLength: 25)
+                : ValuesGenerator.ArrayOfUniqueValues<string>(Count * 2);
+            _array = all.Take(Count).ToArray();
+            _notFound = all.Skip(Count).ToArray();
             _dictionary = _array.ToDictionary(item => item, item => item);
             _immutableDictionary = _dictionary.ToImmutableDictionary();
             _frozenDictionary = _dictionary.ToFrozenDictionary();
 
-            EnsureRightStrategyIsUsed("OrdinalStringFrozenDictionary");
+            Verify("OrdinalStringFrozenDictionary");
         }
     }
 }