I've been doing some JIRA administration and customization for a client, and I ran into a problem that was driving me crazy. I created a new workflow to deal with an Issue Type called Change Request by copying an exsiting workflow. I renamed one of the transitions from "Close Issue" to "Decline CR," and I associated a screen with the transition (the reason for creating a new workflow).
The name of the transition ("Decline CR") displayed correctly in the administration page, but in the regular display page of a Change Request issue, the name of the workflow action was still the old value ("Close Issue") from the original workflow. I tried a few things to fix it, but nothing seemed to help. I even tried changing the workflow scheme and changing it back. Still nothing.
This morning while fishing around in the administration pages, I found the problem. The transition included an internationalization property, jira.i18n.title, that specifies what appears to be the title of the workflow action, closeissue.title. I picked up that property when I cloned the workflow - the ultimate origin of the workflow was the JIRA's default workflow, which was internationalized. Removing the property got the workflow action name ("Decline CR") to display correctly. (I'm not working in a multi-language environment, so I don't need any localization.)