repository insert collection method call findOne of all items if @Id annotated field is valorized

[aprato-visual]

Java doc of repository insert collection method say :

"Inserts the given entities. Assumes the given entities to have not been persisted yet and thus will optimize the insert over a call to saveAll(Iterable). Prefer using saveAll(Iterable) to avoid the usage of storespecific API."

but if @id annotated fields of items in collection are pre valorized, repository first check all id and after this, save data but this degrade the performance of a code like this:
repository.deleteAll(); repository.insert(collection);
is this behavior intentional?