Sometimes, view merge fields will become corrupt and need to be re-added. All you need to do is to follow the steps below:

  1. Remove the Merge View from the template.
  2. Remove the merge view from the available merge fields for that template.
  3. Close Document Template Manager.
  4. Reopen document template manager and re-add the merge view.
This should resolve the corruption and allow all columns to be displayed.