diff --git a/src/coreclr/jit/importer.cpp b/src/coreclr/jit/importer.cpp
index acec2e45f68dc3..fed5a6ad0f2d64 100644
--- a/src/coreclr/jit/importer.cpp
+++ b/src/coreclr/jit/importer.cpp
@@ -5572,13 +5572,20 @@ GenTree* Compiler::impCastClassOrIsInstToTree(
         op2->gtFlags |= GTF_DONT_CSE;
 
         GenTreeCall* call = gtNewHelperCallNode(helper, TYP_REF, op2, op1);
+
+        // Instrument this castclass/isinst
         if ((JitConfig.JitClassProfiling() > 0) && impIsCastHelperEligibleForClassProbe(call) && !isClassExact)
         {
-            HandleHistogramProfileCandidateInfo* pInfo  = new (this, CMK_Inlining) HandleHistogramProfileCandidateInfo;
-            pInfo->ilOffset                             = ilOffset;
-            pInfo->probeIndex                           = info.compHandleHistogramProbeCount++;
-            call->gtHandleHistogramProfileCandidateInfo = pInfo;
-            compCurBB->SetFlags(BBF_HAS_HISTOGRAM_PROFILE);
+            // It doesn't make sense to instrument "x is T" or "(T)x" for shared T
+            if ((info.compCompHnd->getClassAttribs(pResolvedToken->hClass) & CORINFO_FLG_SHAREDINST) == 0)
+            {
+                HandleHistogramProfileCandidateInfo* pInfo =
+                    new (this, CMK_Inlining) HandleHistogramProfileCandidateInfo;
+                pInfo->ilOffset                             = ilOffset;
+                pInfo->probeIndex                           = info.compHandleHistogramProbeCount++;
+                call->gtHandleHistogramProfileCandidateInfo = pInfo;
+                compCurBB->SetFlags(BBF_HAS_HISTOGRAM_PROFILE);
+            }
         }
         return call;
     }
diff --git a/src/coreclr/jit/jitconfigvalues.h b/src/coreclr/jit/jitconfigvalues.h
index cc57aba2cc5edb..753b7451b875c4 100644
--- a/src/coreclr/jit/jitconfigvalues.h
+++ b/src/coreclr/jit/jitconfigvalues.h
@@ -616,7 +616,7 @@ CONFIG_INTEGER(JitMinimalJitProfiling, W("JitMinimalJitProfiling"), 1)
 CONFIG_INTEGER(JitMinimalPrejitProfiling, W("JitMinimalPrejitProfiling"), 0)
 
 CONFIG_INTEGER(JitProfileValues, W("JitProfileValues"), 1) // Value profiling, e.g. Buffer.Memmove's size
-CONFIG_INTEGER(JitProfileCasts, W("JitProfileCasts"), 0)   // Profile castclass/isinst
+CONFIG_INTEGER(JitProfileCasts, W("JitProfileCasts"), 1)   // Profile castclass/isinst
 CONFIG_INTEGER(JitConsumeProfileForCasts, W("JitConsumeProfileForCasts"), 1) // Consume profile data (if any) for
                                                                              // castclass/isinst
 
diff --git a/src/coreclr/tools/superpmi/superpmi-shared/methodcontext.cpp b/src/coreclr/tools/superpmi/superpmi-shared/methodcontext.cpp
index f63042a2def778..a6d49f08219b5b 100644
--- a/src/coreclr/tools/superpmi/superpmi-shared/methodcontext.cpp
+++ b/src/coreclr/tools/superpmi/superpmi-shared/methodcontext.cpp
@@ -6925,8 +6925,14 @@ int MethodContext::repGetIntConfigValue(const WCHAR* name, int defaultValue)
     key.nameIndex    = (DWORD)nameIndex;
     key.defaultValue = defaultValue;
 
-    DWORD value = LookupByKeyOrMissNoMessage(GetIntConfigValue, key);
+    int index = GetIntConfigValue->GetIndex(key);
+    if (index == -1)
+    {
+        // default value has changed
+        return defaultValue;
+    }
 
+    DWORD value = GetIntConfigValue->GetItem(index);
     DEBUG_REP(dmpGetIntConfigValue(key, value));
     return (int)value;
 }