close vercel#832

Author: promer94

src/use-swr.ts

@@ -215,6 +215,10 @@ const mutate: mutateInterface = async (
       if (error) throw error
       return cache.get(key)
     })
+  } else {
+    // eslint-disable-next-line require-atomic-updates
+    MUTATION_TS[key] = undefined
+    MUTATION_END_TS[key] = undefined
   }
   // throw error or return data to be used by caller of mutate
   if (error) throw error