Summary

When trying to rename a JIRA Workflow step to upper or lowercase, JIRA will not allow it to be changed, and it will state that, "A step with that name already exists.".

Steps to reproduce

1. In a workflow, access the 'Text' mode and check the Steps
2. Click on the 'Edit' button, and in the resulting page, try to rename the step name to it's upper or lowercase equivalent. For example, change 'Open' to 'open'
3. It will return the error "A step with that name already exists.", and not allow it to be changed. There are no other steps called 'open' in the workflow

Workaround

This can be bypassed by first renaming the step name to something else entirely first, before changing it again to the lower or uppercase. For example, 'Open' can be changed to 'Open2', and then finally changed to 'open'.