Refiners for multi-valued managed properties do not behave like they do for Site Columns when they are created. Values are being refined to "Value one;Value two;Value three" instead of:
I've seen SharePoint 2010 posts that answer the question but not 2013. Any help would be a appreciated!
Actually separators are not used any longer in SharePoint 2013. The multivalue field needs to be populated using a List of items, e.g. List<string>.
I'm using Content Enrichtment to populate my field using Property<List<string>> ; a good example from Microsoft:
How to: Use the Content Enrichment web service callout for SharePoint Server
I found another interesting sample in the Microsoft forums:
Index a multiple value column in BCS external content type "SharePoint 2013"
Create a custom Filter based on the OOB MultiField one. Split the filters into new filters, instead of hex use the actual plain text value.
I have described everything here: https://hyankov.wordpress.com/2014/12/15/sharepoint-2013-refiner-multi-value-contains-instead-of-an-equals/
The simple answer to this question in SharePoint 2013 is to make the Managed Property 'Allow multiple values'. This is done through Search Schema in the settings list.
This allows a single option to match, even when multi-choices are selected.
