diff --git a/src/Attr.cc b/src/Attr.cc
index 483c98f0ea..dc6ef6e380 100644
--- a/src/Attr.cc
+++ b/src/Attr.cc
@@ -193,7 +193,7 @@ Attributes::Attributes(std::vector<AttrPtr> a,
 		AddAttr(std::move(attr));
 	}
 
-void Attributes::AddAttr(AttrPtr attr)
+void Attributes::AddAttr(AttrPtr attr, bool is_redef)
 	{
 	auto acceptable_duplicate_tag = [&](const AttrPtr& attr, const AttrPtr& existing) -> bool
 		{
@@ -216,9 +216,12 @@ void Attributes::AddAttr(AttrPtr attr)
 	// Display a warning for duplicated tags on a type. &log tags are intentionally
 	// ignored here because duplicate log tags on record types are valid, and don't
 	// cause any significant breakage for other types.
-	auto existing = Find(attr->Tag());
-	if ( existing && ! acceptable_duplicate_tag(attr, existing) )
-		reporter->Error("Duplicate %s tag is ambiguous", attr_name(attr->Tag()));
+	if ( ! is_redef )
+		{
+		auto existing = Find(attr->Tag());
+		if ( existing && ! acceptable_duplicate_tag(attr, existing) )
+			reporter->Error("Duplicate %s tag is ambiguous", attr_name(attr->Tag()));
+		}
 
 	// We overwrite old attributes by deleting them first.
 	RemoveAttr(attr->Tag());
@@ -249,16 +252,16 @@ void Attributes::AddAttr(AttrPtr attr)
 		}
 	}
 
-void Attributes::AddAttrs(const AttributesPtr& a)
+void Attributes::AddAttrs(const AttributesPtr& a, bool is_redef)
 	{
 	for ( const auto& attr : a->GetAttrs() )
-		AddAttr(attr);
+		AddAttr(attr, is_redef);
 	}
 
-void Attributes::AddAttrs(Attributes* a)
+void Attributes::AddAttrs(Attributes* a, bool is_redef)
 	{
 	for ( const auto& attr : a->GetAttrs() )
-		AddAttr(attr);
+		AddAttr(attr, is_redef);
 
 	Unref(a);
 	}
diff --git a/src/Attr.h b/src/Attr.h
index 5c110bfe7f..51344ffff7 100644
--- a/src/Attr.h
+++ b/src/Attr.h
@@ -115,12 +115,12 @@ public:
 
 	~Attributes() override = default;
 
-	void AddAttr(AttrPtr a);
+	void AddAttr(AttrPtr a, bool is_redef = false);
 
-	void AddAttrs(const AttributesPtr& a);
+	void AddAttrs(const AttributesPtr& a, bool is_redef = false);
 
 	[[deprecated("Remove in v4.1. Pass IntrusivePtr instead.")]]
-	void AddAttrs(Attributes* a);	// Unref's 'a' when done
+	void AddAttrs(Attributes* a, bool is_redef = false);	// Unref's 'a' when done
 
 	[[deprecated("Remove in v4.1. Use Find().")]]
 	Attr* FindAttr(AttrTag t) const;
diff --git a/src/ID.cc b/src/ID.cc
index 46dcd50efd..ab4d34bf9e 100644
--- a/src/ID.cc
+++ b/src/ID.cc
@@ -314,10 +314,10 @@ std::string ID::GetDeprecationWarning() const
 		return zeek::util::fmt("deprecated (%s): %s", Name(), result.c_str());
 	}
 
-void ID::AddAttrs(AttributesPtr a)
+void ID::AddAttrs(AttributesPtr a, bool is_redef)
 	{
 	if ( attrs )
-		attrs->AddAttrs(a);
+		attrs->AddAttrs(a, is_redef);
 	else
 		attrs = std::move(a);
 
diff --git a/src/ID.h b/src/ID.h
index 2ea5a41134..a24724013b 100644
--- a/src/ID.h
+++ b/src/ID.h
@@ -121,7 +121,7 @@ public:
 	bool IsRedefinable() const;
 
 	void SetAttrs(AttributesPtr attr);
-	void AddAttrs(AttributesPtr attr);
+	void AddAttrs(AttributesPtr attr, bool is_redef = false);
 	void RemoveAttr(AttrTag a);
 	void UpdateValAttrs();
 
diff --git a/src/Var.cc b/src/Var.cc
index 174704e069..b98c89c317 100644
--- a/src/Var.cc
+++ b/src/Var.cc
@@ -213,7 +213,7 @@ static void make_var(const zeek::detail::IDPtr& id, zeek::TypePtr t,
 	id->SetType(t);
 
 	if ( attr )
-		id->AddAttrs(zeek::make_intrusive<zeek::detail::Attributes>(std::move(*attr), t, false, id->IsGlobal()));
+		id->AddAttrs(zeek::make_intrusive<zeek::detail::Attributes>(std::move(*attr), t, false, id->IsGlobal()), dt == VAR_REDEF);
 
 	if ( init )
 		{