diff --git a/src/native/managed/cdacreader/src/Legacy/SigFormat.cs b/src/native/managed/cdacreader/src/Legacy/SigFormat.cs
index 4ce7832a7bd01..8ce87039b59cd 100644
--- a/src/native/managed/cdacreader/src/Legacy/SigFormat.cs
+++ b/src/native/managed/cdacreader/src/Legacy/SigFormat.cs
@@ -227,9 +227,9 @@ private static unsafe void AddTypeString(Target target,
 
                     case CorElementType.Var:
                         int varIndex = signature.ReadCompressedInteger();
-                        if (methodInstantiation.Length > varIndex)
+                        if (typeInstantiation.Length > varIndex)
                         {
-                            AddType(target, stringBuilder, methodInstantiation[varIndex]);
+                            AddType(target, stringBuilder, typeInstantiation[varIndex]);
                         }
                         else
                         {
diff --git a/src/native/managed/cdacreader/src/Legacy/TypeNameBuilder.cs b/src/native/managed/cdacreader/src/Legacy/TypeNameBuilder.cs
index 45e3a88b6620f..03e600e4778be 100644
--- a/src/native/managed/cdacreader/src/Legacy/TypeNameBuilder.cs
+++ b/src/native/managed/cdacreader/src/Legacy/TypeNameBuilder.cs
@@ -149,6 +149,12 @@ public static void AppendMethodImpl(Target target, StringBuilder stringBuilder,
             if (!th.IsNull)
             {
                 typeInstantiationSigFormat = runtimeTypeSystem.GetInstantiation(th);
+                if (typeInstantiationSigFormat.IsEmpty && runtimeTypeSystem.IsArray(th, out _))
+                {
+                    // For arrays, fill in the instantiation with the element type handle
+                    // See MethodTable::GetArrayInstantiation for coreclr equivalent
+                    typeInstantiationSigFormat = new[] { runtimeTypeSystem.GetTypeParam(th) };
+                }
             }
 
             SigFormat.AppendSigFormat(target, stringBuilder, signature, reader, null, null, null, typeInstantiationSigFormat, runtimeTypeSystem.GetGenericMethodInstantiation(method), true);