diff --git a/graal-js/src/com.oracle.truffle.js.test/js/GR-51680.js b/graal-js/src/com.oracle.truffle.js.test/js/GR-51680.js
new file mode 100644
index 00000000000..8d0a6d49c54
--- /dev/null
+++ b/graal-js/src/com.oracle.truffle.js.test/js/GR-51680.js
@@ -0,0 +1,80 @@
+/*
+ * Copyright (c) 2024, 2024, Oracle and/or its affiliates. All rights reserved.
+ * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
+ *
+ * Licensed under the Universal Permissive License v 1.0 as shown at http://oss.oracle.com/licenses/upl.
+ */
+
+/**
+ * Regression test checking successful transition from sealed JSObjectArray to ObjectArray strategy.
+ *
+ * @option debug-builtin
+ */
+
+load("assert.js");
+
+const o = {};
+const x = 42;
+
+for (const jsobjectArrayType of ["ZeroBasedJSObjectArray", "ContiguousJSObjectArray", "HolesJSObjectArray"]) {
+  const objectArrayType = jsobjectArrayType.replace("JS", "");
+  switch (jsobjectArrayType) {
+    case "ZeroBasedJSObjectArray": {
+      let a = [];
+      for (let i = 0; i < 8; i++) {
+        a[i] = o;
+      }
+      Object.seal(a);
+      assertArrayType(a, jsobjectArrayType);
+
+      a[5] = x;
+
+      assertArrayType(a, objectArrayType);
+      assertSameContent([o,o,o,o,o,x,o,o], a);
+      assertTrue(Object.isSealed(a));
+      break;
+    }
+    case "ContiguousJSObjectArray": {
+      let a = [];
+      for (let i = 1; i < 8; i++) {
+        a[i] = o;
+      }
+      Object.seal(a);
+      assertArrayType(a, jsobjectArrayType);
+
+      a[0] = x;
+      assertArrayType(a, jsobjectArrayType);
+
+      a[5] = x;
+      assertArrayType(a, objectArrayType);
+      assertSameContent([ ,o,o,o,o,x,o,o], a);
+      assertTrue(Object.isSealed(a));
+      break;
+    }
+    case "HolesJSObjectArray": {
+      let a = [];
+      for (let i = 0; i < 8; i++) {
+        if (i == 4) {
+          continue;
+        }
+        a[i] = o;
+      }
+      Object.seal(a);
+      assertArrayType(a, jsobjectArrayType);
+
+      a[4] = x;
+      assertArrayType(a, jsobjectArrayType);
+      a[5] = x;
+
+      assertArrayType(a, objectArrayType);
+      assertSameContent([o,o,o,o, ,x,o,o], a);
+      assertTrue(Object.isSealed(a));
+      break;
+    }
+    default: throw new TypeError(jsobjectArrayType);
+  }
+}
+
+function assertArrayType(array, expected) {
+  assertSame(expected, Debug.arraytype(array))
+}
diff --git a/graal-js/src/com.oracle.truffle.js/src/com/oracle/truffle/js/nodes/interop/ArrayElementInfoNode.java b/graal-js/src/com.oracle.truffle.js/src/com/oracle/truffle/js/nodes/interop/ArrayElementInfoNode.java
index a3deb7f8cbc..f93efe2f354 100644
--- a/graal-js/src/com.oracle.truffle.js/src/com/oracle/truffle/js/nodes/interop/ArrayElementInfoNode.java
+++ b/graal-js/src/com.oracle.truffle.js/src/com/oracle/truffle/js/nodes/interop/ArrayElementInfoNode.java
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2020, 2020, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2020, 2024, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * The Universal Permissive License (UPL), Version 1.0
@@ -49,6 +49,7 @@
 import com.oracle.truffle.js.nodes.JavaScriptBaseNode;
 import com.oracle.truffle.js.runtime.JSRuntime;
 import com.oracle.truffle.js.runtime.array.ScriptArray;
+import com.oracle.truffle.js.runtime.builtins.JSAbstractArray;
 import com.oracle.truffle.js.runtime.builtins.JSArrayBase;
 
 /**
@@ -99,7 +100,7 @@ static TriState doCached(JSArrayBase target, long index, int query,
                 return TriState.UNDEFINED;
             }
         }
-        if (index >= 0 && index < arrayType.length(target)) {
+        if (index >= 0 && index < JSAbstractArray.arrayGetLength(target)) {
             if ((query & READABLE) != 0) {
                 return TriState.TRUE;
             }
diff --git a/graal-js/src/com.oracle.truffle.js/src/com/oracle/truffle/js/runtime/array/dyn/AbstractJSObjectArray.java b/graal-js/src/com.oracle.truffle.js/src/com/oracle/truffle/js/runtime/array/dyn/AbstractJSObjectArray.java
index dd9c2ba7d77..b605531db45 100644
--- a/graal-js/src/com.oracle.truffle.js/src/com/oracle/truffle/js/runtime/array/dyn/AbstractJSObjectArray.java
+++ b/graal-js/src/com.oracle.truffle.js/src/com/oracle/truffle/js/runtime/array/dyn/AbstractJSObjectArray.java
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2018, 2023, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2018, 2024, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * The Universal Permissive License (UPL), Version 1.0
@@ -78,10 +78,15 @@ public final ScriptArray setElementImpl(JSDynamicObject object, long index, Obje
     }
 
     private ScriptArray rewrite(JSDynamicObject object, long index, Object value) {
-        if (isSupportedContiguous(object, index)) {
-            return toContiguous(object, index, value);
-        } else if (isSupportedHoles(object, index)) {
-            return toHoles(object, index, value);
+        if (JSDynamicObject.isJSDynamicObject(value)) {
+            assert !isSupported(object, index);
+            if (isSupportedContiguous(object, index)) {
+                return toContiguous(object, index, value);
+            } else if (isSupportedHoles(object, index)) {
+                return toHoles(object, index, value);
+            } else {
+                return toSparse(object, index, value);
+            }
         } else {
             return toObject(object, index, value);
         }