diff --git a/include/nlohmann/json.hpp b/include/nlohmann/json.hpp
index fc3e60828..053be8f74 100644
--- a/include/nlohmann/json.hpp
+++ b/include/nlohmann/json.hpp
@@ -6009,6 +6009,9 @@ class basic_json // NOLINT(cppcoreguidelines-special-member-functions,hicpp-spec
         for (auto it = j.cbegin(); it != j.cend(); ++it)
         {
             m_value.object->operator[](it.key()) = it.value();
+#if JSON_DIAGNOSTICS
+            m_value.object->operator[](it.key()).m_parent = this;
+#endif
         }
     }
 
@@ -6069,6 +6072,9 @@ class basic_json // NOLINT(cppcoreguidelines-special-member-functions,hicpp-spec
         for (auto it = first; it != last; ++it)
         {
             m_value.object->operator[](it.key()) = it.value();
+#if JSON_DIAGNOSTICS
+            m_value.object->operator[](it.key()).m_parent = this;
+#endif
         }
     }
 
diff --git a/single_include/nlohmann/json.hpp b/single_include/nlohmann/json.hpp
index 8959265da..803a83c39 100644
--- a/single_include/nlohmann/json.hpp
+++ b/single_include/nlohmann/json.hpp
@@ -23414,6 +23414,9 @@ class basic_json // NOLINT(cppcoreguidelines-special-member-functions,hicpp-spec
         for (auto it = j.cbegin(); it != j.cend(); ++it)
         {
             m_value.object->operator[](it.key()) = it.value();
+#if JSON_DIAGNOSTICS
+            m_value.object->operator[](it.key()).m_parent = this;
+#endif
         }
     }
 
@@ -23474,6 +23477,9 @@ class basic_json // NOLINT(cppcoreguidelines-special-member-functions,hicpp-spec
         for (auto it = first; it != last; ++it)
         {
             m_value.object->operator[](it.key()) = it.value();
+#if JSON_DIAGNOSTICS
+            m_value.object->operator[](it.key()).m_parent = this;
+#endif
         }
     }
 
diff --git a/test/src/unit-diagnostics.cpp b/test/src/unit-diagnostics.cpp
index d4bbf93aa..8e4f2ffc3 100644
--- a/test/src/unit-diagnostics.cpp
+++ b/test/src/unit-diagnostics.cpp
@@ -184,4 +184,54 @@ TEST_CASE("Better diagnostics")
         j["second"] = value;
         j2["something"] = j;
     }
+
+    SECTION("Regression test for issue #3007 - Parent pointers properly set when using update()")
+    {
+        // void update(const_reference j)
+        {
+            json j = json::object();
+
+            {
+                json j2 = json::object();
+                j2["one"] = 1;
+
+                j.update(j2);
+            }
+
+            // Must call operator[] on const element, otherwise m_parent gets updated.
+            auto const& constJ = j;
+            CHECK_THROWS_WITH_AS(constJ["one"].at(0), "[json.exception.type_error.304] (/one) cannot use at() with number", json::type_error);
+        }
+
+        // void update(const_iterator first, const_iterator last)
+        {
+            json j = json::object();
+
+            {
+                json j2 = json::object();
+                j2["one"] = 1;
+
+                j.update(j2.begin(), j2.end());
+            }
+
+            // Must call operator[] on const element, otherwise m_parent gets updated.
+            auto const& constJ = j;
+            CHECK_THROWS_WITH_AS(constJ["one"].at(0), "[json.exception.type_error.304] (/one) cannot use at() with number", json::type_error);
+        }
+
+        // Code from #3007 triggering unwanted assertion without fix to update().
+        {
+            json root = json::array();
+            json lower = json::object();
+
+            {
+                json lowest = json::object();
+                lowest["one"] = 1;
+
+                lower.update(lowest);
+            }
+
+            root.push_back(lower);
+        }
+    }
 }