Issue Summary

Work Code field mapped in Field Management is automatically removed after we click on save button on Jira Setup configuration tab.

This is reproducible on Data Center: (yes) / (no)

Steps to Reproduce

1. Map Work Code as a text custom field in Jira
   1. Note after saving the configuration it's confirmed by green toaster at the top
2. Navigate to Administration -> Jira Settings -> Jira Setup
3. Save the configuration without making any changes.
4. Work Code field mapping is getting removed automatically from Field Management Tab.
5. Change Log (Manage Projects-> View Logs) showing the Work Code field is removed by the user.

Expected Results

Work code mapping on the Field management tab should not be cleaned up after we click on the save button on the Jira Setup configuration tab.

Actual Results

No log files evidencing it.
Work code mapping is being cleaned up after hitting saving in the Jira Setup tab 

...

Workaround

No workaround so far.