Keyword tags generated from metadata extraction are formed into a single string rather than split on delimiter

Description

Multiple keyword tags are not being split on the comma delimiter, instead they are being added as one long tag (that includes the comma)

In 5.0.1, the behavior is different as only the first word is used as a tag, the rest are ignored.

Steps to reproduce

1. Install 5.0.2.5 Alfresco
2. Place the attached 'metadata-context.xml' and 'TikaAutoMetadataExtracter.properties' into the ~/shared/classes/alfresco/extension
3. Upload various documents containing metadata to repository (example PDF attached)
4. Browse to document library, select a document and view its tags

Expected behaviour

All tags are separated and individual tags created for each string

Observed Behaviour

Metadata tags are not being split on delimiter (comma) and are shown as one long tag, made up of all the tags (see attached error.png)