diff --git a/src/services/skillSearch/localSearch.ts b/src/services/skillSearch/localSearch.ts
index c7c00dc39..f0bd553d8 100644
--- a/src/services/skillSearch/localSearch.ts
+++ b/src/services/skillSearch/localSearch.ts
@@ -397,7 +397,7 @@ export function searchSkills(
   for (const v of freq.values()) if (v > max) max = v
   for (const [term, count] of freq) queryTf.set(term, count / max)
 
-  const idf = cachedIdf ?? computeIdf(index)
+  const idf = cachedIndex === index && cachedIdf ? cachedIdf : computeIdf(index)
   const queryTfIdf = new Map<string, number>()
   for (const [term, tf] of queryTf) {
     queryTfIdf.set(term, tf * (idf.get(term) ?? 0))