Strange result sorting in Search Web Part SharePoint 2013

Question

We have a Search Web parts with a Sorting drop down list.

In the Query config panel, the default sort is on the "ranking".

However, in the Web Part we have the following JSON to present a drop down list of "Sorting" options for the users. [{"name":"Ranking","sorts":[]},{"name":"Date(from latest)","sorts":[{"p":"Write","d":1}]},{"name":"Date(from oldest)","sorts":[{"p":"Write","d":0}]},{"name":"Title (A - Z)","sorts":[{"p":"Title","d":0}]},{"name":"Title (Z - A)","sorts":[{"p":"Title","d":1}]}]

We have some problems when use the Sort Drop Down List. Selecting for example "Title (A - Z)" does not result in an alphabetical sorting of all the results. Sometimes A is placed after C or D...etc.

The sort code in which is called on the OnChange of the sort Drop Down List is quite standard onchange="$getClientControl(this).sortOrRank(this.value);

Now I'm a little puzzled by the resulting sort.

Answer 1

This rings a bell. As I recall it the reason could be that the Title field is not mapped to a sortable nor refinable managed property. Try to have a look at the basic:Title managed property in the search schema