Issue Summary

If a Jira user creates a new custom field using the Target Start or Target End field types, these new fields will pull the data already available to the default Target Start/End fields.

Steps to Reproduce

1. Create a custom field using Target Start, and name it something obvious like "TARGET START 2".
2. Add this new field to the view issue screen of your project so you can see it's value. (None yet.)
3. Go to a Portfolio Plan for the Project that uses this field, change the normal Target Start field for an issue, and commit this back to Jira.
4. 
5. View that same issue in Jira, and observe the TARGET START 2 fields holds the same data as what you input into the original Target Start field in JPO. 
6. 

Expected Results

This would an entirely separate field with its own stored values.

Actual Results

Any new custom field of the Target Start type gets the data from the original Target Start field.

Workaround

Use a date field instead of the "Target" fields.