diff --git a/packages/svelte/src/internal/server/hydratable.js b/packages/svelte/src/internal/server/hydratable.js
index d8979ad7f5..3beb5d50c2 100644
--- a/packages/svelte/src/internal/server/hydratable.js
+++ b/packages/svelte/src/internal/server/hydratable.js
@@ -24,7 +24,7 @@ export function hydratable(key, fn) {
 	let entry = hydratable.lookup.get(key);
 
 	if (entry !== undefined) {
-		if (DEV && entry.dev) {
+		if (DEV) {
 			const comparison = compare(key, entry, encode(key, fn(), []));
 			comparison.catch(() => {});
 			hydratable.comparisons.push(comparison);
@@ -52,11 +52,7 @@ function encode(key, value, values, unresolved) {
 	const entry = { value, index: -1 };
 
 	if (DEV) {
-		entry.dev = {
-			serialized: undefined,
-			serialize_work: [],
-			stack: get_stack('hydratable')?.stack
-		};
+		entry.stack = get_stack('hydratable')?.stack;
 	}
 
 	let needs_thunk = false;
@@ -82,12 +78,11 @@ function encode(key, value, values, unresolved) {
 			// of a given hydratable are identical with a simple string comparison
 			const result = DEV ? `d("${index}")` : `d(${index})`;
 
-			if (DEV && entry.dev) {
-				const { dev } = entry;
-				dev.serialize_work.push(
+			if (DEV) {
+				(entry.serialize_work ??= []).push(
 					serialize_promise.then((s) => {
 						serialized = serialized.replace(result, s);
-						dev.serialized = serialized;
+						entry.serialized = serialized;
 					})
 				);
 			}
@@ -96,6 +91,7 @@ function encode(key, value, values, unresolved) {
 		}
 	});
 
+	entry.serialized = serialized;
 	entry.index = values.push(needs_thunk ? `()=>(${serialized})` : serialized) - 1;
 	needs_thunk = false;
 
@@ -111,19 +107,19 @@ async function compare(key, a, b) {
 	// note: these need to be loops (as opposed to Promise.all) because
 	// additional promises can get pushed to them while we're awaiting
 	// an earlier one
-	for (const p of a.dev?.serialize_work ?? []) {
+	for (const p of a?.serialize_work ?? []) {
 		await p;
 	}
 
-	for (const p of b.dev?.serialize_work ?? []) {
+	for (const p of b?.serialize_work ?? []) {
 		await p;
 	}
 
-	if (a.dev?.serialized !== b.dev?.serialized) {
+	if (a?.serialized !== b?.serialized) {
 		e.hydratable_clobbering(
 			key,
-			a.dev?.stack ?? '<missing stack trace>',
-			b.dev?.stack ?? '<missing stack trace>'
+			a?.stack ?? '<missing stack trace>',
+			b?.stack ?? '<missing stack trace>'
 		);
 	}
 }
diff --git a/packages/svelte/src/internal/server/renderer.js b/packages/svelte/src/internal/server/renderer.js
index 53be330aa1..75a39b436f 100644
--- a/packages/svelte/src/internal/server/renderer.js
+++ b/packages/svelte/src/internal/server/renderer.js
@@ -580,7 +580,7 @@ export class Renderer {
 		for (const [_, key] of ctx.unresolved_promises) {
 			// this is a problem -- it means we've finished the render but we're still waiting on a promise to resolve so we can
 			// serialize it, so we're blocking the response on useless content.
-			w.unresolved_hydratable(key, ctx.lookup.get(key)?.dev?.stack ?? '<missing stack trace>');
+			w.unresolved_hydratable(key, ctx.lookup.get(key)?.stack ?? '<missing stack trace>');
 		}
 
 		for (const comparison of ctx.comparisons) {
diff --git a/packages/svelte/src/internal/server/types.d.ts b/packages/svelte/src/internal/server/types.d.ts
index 6728d4752e..26bc09ea95 100644
--- a/packages/svelte/src/internal/server/types.d.ts
+++ b/packages/svelte/src/internal/server/types.d.ts
@@ -18,11 +18,12 @@ export interface SSRContext {
 export interface HydratableLookupEntry {
 	value: unknown;
 	index: number;
-	dev?: {
-		serialize_work: Array<Promise<void>>;
-		serialized: string | undefined;
-		stack: string | undefined;
-	};
+	/** dev-only */
+	serialize_work?: Array<Promise<void>>;
+	/** dev-only */
+	serialized?: string;
+	/** dev-only */
+	stack?: string;
 }
 
 export interface HydratableContext {
diff --git a/packages/svelte/tests/runtime-runes/samples/hydratable-complex-nesting/_config.js b/packages/svelte/tests/runtime-runes/samples/hydratable-complex-nesting/_config.js
new file mode 100644
index 0000000000..0ac5333c4a
--- /dev/null
+++ b/packages/svelte/tests/runtime-runes/samples/hydratable-complex-nesting/_config.js
@@ -0,0 +1,24 @@
+import { tick } from 'svelte';
+import { ok, test } from '../../test';
+
+export default test({
+	skip_no_async: true,
+	skip_mode: ['server'],
+
+	server_props: { environment: 'server' },
+	ssrHtml: '<p>The current environment is: server</p>',
+
+	props: { environment: 'browser' },
+
+	async test({ assert, target, variant }) {
+		// make sure hydration has a chance to finish
+		await tick();
+		const p = target.querySelector('p');
+		ok(p);
+		if (variant === 'hydrate') {
+			assert.htmlEqual(p.outerHTML, '<p>The current environment is: server</p>');
+		} else {
+			assert.htmlEqual(p.outerHTML, '<p>The current environment is: browser</p>');
+		}
+	}
+});
diff --git a/packages/svelte/tests/runtime-runes/samples/hydratable-complex-nesting/main.svelte b/packages/svelte/tests/runtime-runes/samples/hydratable-complex-nesting/main.svelte
new file mode 100644
index 0000000000..cd603a6e6b
--- /dev/null
+++ b/packages/svelte/tests/runtime-runes/samples/hydratable-complex-nesting/main.svelte
@@ -0,0 +1,13 @@
+<script lang="ts">
+	import { hydratable } from "svelte";
+
+	let { environment } = $props();
+
+	const value = hydratable("environment", () => Promise.resolve({
+		nested: Promise.resolve({
+			environment
+		})
+	}))
+</script>
+
+<p>The current environment is: {await value.then(res => res.nested).then(res => res.environment)}</p>
diff --git a/packages/svelte/tests/server-side-rendering/samples/hydratable-clobbering-complicated/_config.js b/packages/svelte/tests/server-side-rendering/samples/hydratable-clobbering-complicated/_config.js
new file mode 100644
index 0000000000..404260cc66
--- /dev/null
+++ b/packages/svelte/tests/server-side-rendering/samples/hydratable-clobbering-complicated/_config.js
@@ -0,0 +1,6 @@
+import { test } from '../../test';
+
+export default test({
+	mode: ['async'],
+	error: 'hydratable_clobbering'
+});
diff --git a/packages/svelte/tests/server-side-rendering/samples/hydratable-clobbering-complicated/main.svelte b/packages/svelte/tests/server-side-rendering/samples/hydratable-clobbering-complicated/main.svelte
new file mode 100644
index 0000000000..358488c3ac
--- /dev/null
+++ b/packages/svelte/tests/server-side-rendering/samples/hydratable-clobbering-complicated/main.svelte
@@ -0,0 +1,16 @@
+<script lang="ts">
+    import { hydratable } from 'svelte';
+
+    hydratable('key', () => Promise.resolve({
+        nested: Promise.resolve({
+            one: Promise.resolve(1),
+        }),
+        two: Promise.resolve(2),
+    }));
+    hydratable('key', () => Promise.resolve({
+        nested: Promise.resolve({
+            one: Promise.resolve(2),
+        }),
+        two: Promise.resolve(2),
+    }));
+</script>
\ No newline at end of file