Unknown mouth title is displayed incorrectly on skin editor

Summary:

On the "Mouth" section of the skin editor, a title of a unknown mouth is displayed incorrectly.

The mouth work's normaly.

Steps to reproduce: 

1. Go to the skin editor.
2. Select Body -> Mouths.
3. Select the mouth showed in the image above.

Observed results:

The title of the the mouth shows:

"PERSONA.DR.DEFAULT.STEVE.MOUTH.TITLE"

Expected results:

The mouth's title is showed corrrectly.