unique index does not throw DuplicateKeyError

ratelimitOverrides.createIndex((row) => [row.namespaceId, row.identifier], {
  name: 'unique_identifier_per_namespace',
  options: {
    unique: true,
  },
})

try {
  collection.ratelimitOverrides.insert({...});
} catch (error) {
  if (error instanceof DuplicateKeyError) {
     setError("identifier", { type: "custom", message: "Identifier already exists" });
  } else {
    console.error(error)
  }
  
}