When you create a custom field and give it a description, that description correctly appears under the field on all applicable screens. However, if you "Edit Custom Field Details" and change the description, the change will not take effect. The new description can only be displayed if you:

• Go to System > Issue Fields > Field Configurations and open the proper field configuration.
• Find your custom field and edit its description (using the "Edit" link on the right of the field).

This is a request to automatically propagate the changes in custom field descriptions to the proper field configurations, so the change in any custom field details can be displayed.