Objective Tree: Column "Target Completion" is not showing after being selected

Issue Summary

This is reproducible on Data Center: (yes) 

In the old view when in list view mode, after selecting the column "Target Completion" to be displayed in the "Columns Shown" section the page refreshes but the column is not displayed

Steps to Reproduce

1. Set a portfolio for T1
2. In the left menu, access the Objective Tree page
3. Click on "Portfolio Objectives" and then click on the "List View" button
4. Click on the "columns Shown" section and then select the column "Target Completion" and then click on save

Prerequisites: 
For objectives or goals to be available in the Choose Root dropdown, they must be in the portfolio, program, PI, etc selected in the Configuration bar at the top of the page

Expected Results

the column "Target Completion" is displayed after the pages refreshes 

Actual Results

The "Target Completion" is not shown

Workaround

Currently, there is no known workaround for this behavior besides using the new Objective Tree View