diff --git a/src/coreclr/jit/lclvars.cpp b/src/coreclr/jit/lclvars.cpp
index 5f6352d8fc2e6..f158eb485ca60 100644
--- a/src/coreclr/jit/lclvars.cpp
+++ b/src/coreclr/jit/lclvars.cpp
@@ -3169,37 +3169,35 @@ void Compiler::lvaUpdateClass(unsigned varNum, CORINFO_CLASS_HANDLE clsHnd, bool
     assert(varDsc->lvSingleDef);
 
     // Now see if we should update.
-    //
+
     // New information may not always be "better" so do some
     // simple analysis to decide if the update is worthwhile.
     const bool isNewClass   = (clsHnd != varDsc->lvClassHnd);
     bool       shouldUpdate = false;
 
-    // Are we attempting to update the class? Only check this when we have
-    // an new type and the existing class is inexact... we should not be
-    // updating exact classes.
-    if (!varDsc->lvClassIsExact && isNewClass)
+    // Are we attempting to update exactness?
+    if (isExact && !varDsc->lvClassIsExact)
     {
-        shouldUpdate = !!info.compCompHnd->isMoreSpecificType(varDsc->lvClassHnd, clsHnd);
+        shouldUpdate = true;
     }
-    // Else are we attempting to update exactness?
-    else if (isExact && !varDsc->lvClassIsExact && !isNewClass)
+    // Are we attempting to update the class?
+    else if (isNewClass)
     {
-        shouldUpdate = true;
+        shouldUpdate = !!info.compCompHnd->isMoreSpecificType(varDsc->lvClassHnd, clsHnd);
     }
 
-#if DEBUG
-    if (isNewClass || (isExact != varDsc->lvClassIsExact))
+    if (shouldUpdate)
     {
+#if DEBUG
         JITDUMP("\nlvaUpdateClass:%s Updating class for V%02u", shouldUpdate ? "" : " NOT", varNum);
         JITDUMP(" from (%p) %s%s", dspPtr(varDsc->lvClassHnd), eeGetClassName(varDsc->lvClassHnd),
                 varDsc->lvClassIsExact ? " [exact]" : "");
         JITDUMP(" to (%p) %s%s\n", dspPtr(clsHnd), eeGetClassName(clsHnd), isExact ? " [exact]" : "");
-    }
 #endif // DEBUG
 
-    if (shouldUpdate)
-    {
+        assert(!varDsc->lvClassIsExact ||
+               ((info.compCompHnd->getClassAttribs(varDsc->lvClassHnd) & CORINFO_FLG_SHAREDINST) != 0));
+
         varDsc->lvClassHnd     = clsHnd;
         varDsc->lvClassIsExact = isExact;
 
diff --git a/src/coreclr/tools/Common/JitInterface/CorInfoImpl.cs b/src/coreclr/tools/Common/JitInterface/CorInfoImpl.cs
index 453e80c381e5c..a20eb57a22507 100644
--- a/src/coreclr/tools/Common/JitInterface/CorInfoImpl.cs
+++ b/src/coreclr/tools/Common/JitInterface/CorInfoImpl.cs
@@ -2860,8 +2860,9 @@ private bool isMoreSpecificType(CORINFO_CLASS_STRUCT_* cls1, CORINFO_CLASS_STRUC
             if (isType1CanonSubtype != isType2CanonSubtype)
             {
                 // Only one of type1 and type2 is shared.
-                // type2 is more specific if type1 is the shared type.
-                return isType1CanonSubtype;
+                // type2 is more specific if type1 can't be assigned there.
+                return isType1CanonSubtype && !type1.CanCastTo(type2) ||
+                        isType2CanonSubtype && type2.CanCastTo(type1);
             }
 
             // Otherwise both types are either shared or not shared.
diff --git a/src/coreclr/vm/jitinterface.cpp b/src/coreclr/vm/jitinterface.cpp
index b7dcf9eacd88e..c1dd47a747dec 100644
--- a/src/coreclr/vm/jitinterface.cpp
+++ b/src/coreclr/vm/jitinterface.cpp
@@ -4563,8 +4563,9 @@ static BOOL isMoreSpecificTypeHelper(
     if (isHnd1CanonSubtype != isHnd2CanonSubtype)
     {
         // Only one of hnd1 and hnd2 is shared.
-        // hdn2 is more specific if hnd1 is the shared type.
-        return isHnd1CanonSubtype;
+        // hdn2 is more specific if hnd1 can't be assigned there.
+        return (isHnd1CanonSubtype && !hnd1.CanCastTo(hnd2)) ||
+                (isHnd2CanonSubtype && hnd2.CanCastTo(hnd1));
     }
 
     // Otherwise both types are either shared or not shared.