diff --git a/studio-v2/app/vocabulary/components/UnitBuilder.tsx b/studio-v2/app/vocabulary/components/UnitBuilder.tsx
index 6fc5ee3..379340c 100644
--- a/studio-v2/app/vocabulary/components/UnitBuilder.tsx
+++ b/studio-v2/app/vocabulary/components/UnitBuilder.tsx
@@ -58,7 +58,7 @@ export default function UnitBuilder({
   const [manualTarget, setManualTarget] = useState('')
   const [suggestions, setSuggestions] = useState<{ source_text: string; target_text: string; pos?: string }[]>([])
   const [isLookingUp, setIsLookingUp] = useState(false)
-  const debounceRef = useRef<ReturnType<typeof setTimeout>>()
+  const debounceRef = useRef<ReturnType<typeof setTimeout>>(null)
 
   // Auto-suggest translation when typing in source field
   useEffect(() => {