Taxonomy mapping not functioning in Feeds 7.x

I am trying to tag RSS Feed Items by mapping multiple, separate tags defined in the Feed content type using a taxonomy. I would like the tags in the Feed content type to auto populate a field called 'Tags' which I have added to the Feed Item content type.

I have created a new taxonomy called Tags in order to start tagging the RSS Feeds.

I then went to Structure > Content types > Feed and added a new field labelled 'Tags' as an existing field with the widget type of 'Autocomplete term widget (tagging)'.

I repeated the same process of adding the 'Tags' field for Structure > Content types > Feed Item.

In the 'Manage Fields' screen of the Feed content type, I have added a default value of 'news' in the 'Default Value' field.

I have used an RSS Feed Importer. In the basic settings under 'Attach to content type' I have selected 'Feed'. For the Node processor settings, under 'Content Type', I have selected 'Feed Item'.

I have created some RSS Feed content types and I have tested that they are sucessfully importing Feed Items.

I then configured a mapping for the Feed Importer Node processor and added 'Feed node: Taxonomy: Tags' as a source with a target of the 'Tags' field.

After the taxonomy mapping was added to the Feed Importer, the Feed import function failed to work and the Feed content type page would not reload after running the 'Import Items' function. If the taxonomy mapping is removed, the import function on the Feed content type Import tab works again.

Is this a bug or am I missing a setting or a configuration somewhere?