Summary

If we disable all the languages in JIRA except US English the Custom fields screens become blank until any other language is enabled.

Step to Reproduce

1. Set system language English US
2. Navigate to Manage Add-on and select all app from the drop down
3. Disable all the languages except English US

Excepted result

There is no impact on the custom filed screen

Actual Result

The Custom field screens become blank

Workaround

Enable any other Language.