Currently bulk operations like this:

var ubo =  db.collName.initializeUnorderedBulkOp();
for (var h=0; h<newDocArray.length; h++) {
  bulkr.find({"_id":newDocArray[h]._id}).replaceOne(newDocArray[h]);
}
ubo.execute();

report nothing in the {{BulkWriteResult object }} object for documents in the newDocArray whose _id values don't match any documents in the collName collection. This feature request is to add reporting on the number of documents found by each operation.