Sitecore Search Orderby

I am seeing a very strange behaviour from the Sitecore 7.1 Search when ordering by a string field. The code is something like this:

var indexableItem = new SitecoreIndexableItem(Sitecore.Context.Item);
var searchIndex = ContentSearchManager.GetIndex(indexableItem);
var context = searchIndex.CreateSearchContext();
var results = new List<Item>();
var count = 0;
var totalSearchResults = 0;

var contactColleagues = context.GetQueryable<SearchResultItem>()
    .FirstOrDefault(x => x.ItemId == Sitecore.Context.Item.ID);

if (contactColleagues != null)
{
    var items = contactColleagues.GetDescendants<ColleagueSearchResultItem>(context)
                                 .Where(x => x.TemplateId == Templates.Colleague);

    items = items.OrderBy(x => x.Surname);

    var resultItems = items.Page(this.PageNumber, PageSize).GetResults();
}

This all works as expected and returns my dataset ordered by surname as expected. That is until a certainly individual comes along who's surname is "Or". Now Sitecore returns this persons name at the start of the list, no matter what we do.

After some testing I found the same issue happened if I decided to call someone "Andy And", this would appear at the being of the list before "Jeff Aardvark".

I'm assuming this is a bug in the way the data is being presented to the Lucene index.

Has anyone come across this, or have any thoughts about how this could be worked around?

Thanks in advance.

Solution

I think you have a problem with stop words. The default analyzer removes them when the item is crawled. You can however prevent this behaviour.

This post explains how to to turn off the stop words filter:

http://blog.horizontalintegration.com/2015/01/08/sitecore-standard-analyzer-turn-off-the-stop-words-filter/