diff --git a/src/runtime/internal/dom.ts b/src/runtime/internal/dom.ts
index b0cc2c584181..39af01a7c3b6 100644
--- a/src/runtime/internal/dom.ts
+++ b/src/runtime/internal/dom.ts
@@ -22,7 +22,7 @@ export function append(target: Node, node: Node) {
 	if (is_hydrating) {
 		nodes_to_detach.delete(node);
 	}
-	if (node.parentNode !== target) {
+	if (node.parentNode !== target || node.parentNode !== null) {
 		target.appendChild(node);
 	}
 }
@@ -31,7 +31,7 @@ export function insert(target: Node, node: Node, anchor?: Node) {
 	if (is_hydrating) {
 		nodes_to_detach.delete(node);
 	}
-	if (node.parentNode !== target || (anchor && node.nextSibling !== anchor)) {
+	if (node.parentNode !== target || node.parentNode !== null || (anchor && node.nextSibling !== anchor)) {
 		target.insertBefore(node, anchor || null);
 	}
 }
diff --git a/test/hydration/samples/element-nested-sibling/_after.html b/test/hydration/samples/element-nested-sibling/_after.html
new file mode 100644
index 000000000000..d011cf6e3867
--- /dev/null
+++ b/test/hydration/samples/element-nested-sibling/_after.html
@@ -0,0 +1,4 @@
+<p>
+	<span>1</span>
+	<code>2</code>
+</p>
diff --git a/test/hydration/samples/element-nested-sibling/_before.html b/test/hydration/samples/element-nested-sibling/_before.html
new file mode 100644
index 000000000000..d011cf6e3867
--- /dev/null
+++ b/test/hydration/samples/element-nested-sibling/_before.html
@@ -0,0 +1,4 @@
+<p>
+	<span>1</span>
+	<code>2</code>
+</p>
diff --git a/test/hydration/samples/element-nested-sibling/_config.js b/test/hydration/samples/element-nested-sibling/_config.js
new file mode 100644
index 000000000000..8410fc189d95
--- /dev/null
+++ b/test/hydration/samples/element-nested-sibling/_config.js
@@ -0,0 +1,19 @@
+export default {
+	snapshot(target) {
+		const p = target.querySelector('p');
+
+		return {
+			p,
+			span: p.querySelector('span'),
+			code: p.querySelector('code')
+		};
+	},
+
+	test(assert, target, snapshot) {
+		const p = target.querySelector('p');
+
+		assert.equal(p, snapshot.p);
+		assert.equal(p.querySelector('span'), snapshot.span);
+		assert.equal(p.querySelector('code'), snapshot.code);
+	}
+};
diff --git a/test/hydration/samples/element-nested-sibling/main.svelte b/test/hydration/samples/element-nested-sibling/main.svelte
new file mode 100644
index 000000000000..d6e02107e2c2
--- /dev/null
+++ b/test/hydration/samples/element-nested-sibling/main.svelte
@@ -0,0 +1,6 @@
+<p>
+    <span>1</span>
+    {#if true}
+        <code>2</code>
+    {/if}
+</p>
diff --git a/test/hydration/samples/expression-sibling/_after.html b/test/hydration/samples/expression-sibling/_after.html
new file mode 100644
index 000000000000..9c0a0b57788f
--- /dev/null
+++ b/test/hydration/samples/expression-sibling/_after.html
@@ -0,0 +1 @@
+<p>1 2 <span>3</span></p>
diff --git a/test/hydration/samples/expression-sibling/_before.html b/test/hydration/samples/expression-sibling/_before.html
new file mode 100644
index 000000000000..9c0a0b57788f
--- /dev/null
+++ b/test/hydration/samples/expression-sibling/_before.html
@@ -0,0 +1 @@
+<p>1 2 <span>3</span></p>
diff --git a/test/hydration/samples/expression-sibling/_config.js b/test/hydration/samples/expression-sibling/_config.js
new file mode 100644
index 000000000000..c6d3ef3f2f76
--- /dev/null
+++ b/test/hydration/samples/expression-sibling/_config.js
@@ -0,0 +1,19 @@
+export default {
+	snapshot(target) {
+		const p = target.querySelector('p');
+
+		return {
+			p,
+			text: p.childNodes[0],
+			span: p.querySelector('span')
+		};
+	},
+
+	test(assert, target, snapshot) {
+		const p = target.querySelector('p');
+
+		assert.equal(p, snapshot.p);
+		assert.equal(p.childNodes[0], snapshot.text);
+		assert.equal(p.querySelector('span'), snapshot.span);
+	}
+};
diff --git a/test/hydration/samples/expression-sibling/main.svelte b/test/hydration/samples/expression-sibling/main.svelte
new file mode 100644
index 000000000000..65aa541e9cc0
--- /dev/null
+++ b/test/hydration/samples/expression-sibling/main.svelte
@@ -0,0 +1 @@
+<p>{1} 2 <span>3</span></p>