diff --git a/frontend/src/lib/components/Editor.svelte b/frontend/src/lib/components/Editor.svelte
index c3125dd9ce..f518632483 100644
--- a/frontend/src/lib/components/Editor.svelte
+++ b/frontend/src/lib/components/Editor.svelte
@@ -2203,6 +2203,12 @@
 		} else {
 			ed.setValue(next)
 		}
+		// The write above went through `onDidChangeModelContent`, which arms the
+		// keystroke debounce as if the user had typed. Monaco now holds exactly
+		// `code`, so there is nothing to flush — and leaving the timer armed makes
+		// every "is Monaco the newer side?" check (notably the unmount flush) answer
+		// yes on the strength of our own write.
+		cancelPendingChanges()
 	}
 
 	// External `code` prop changes should flow into the Monaco editor. Skip
diff --git a/frontend/src/lib/components/ScriptEditor.svelte b/frontend/src/lib/components/ScriptEditor.svelte
index dd06a58cde..8110805179 100644
--- a/frontend/src/lib/components/ScriptEditor.svelte
+++ b/frontend/src/lib/components/ScriptEditor.svelte
@@ -2762,7 +2762,11 @@
 			awareness={wsProvider?.awareness}
 			on:change={(e) => {
 				if (activeModuleTab === null) {
-					code = editorCode
+					// The payload, not `editorCode`: the editor also fires this while it is
+					// being torn down (the unmount flush), and a destroyed component's
+					// `bind:` writes no longer reach us — re-reading would take the value
+					// from before the change and write it back over `code`.
+					code = e.detail
 					lastSyncedCode = code
 					inferSchema(e.detail)
 				} else {