Hello Sharona32,
It's possible that the template is damaged. What we can do to fix this is make a copy of the original template by following these steps:
- Go to Lists > Templates.
- Highlight the template you want to copy and click the Templates drop-down located at the bottom left.
- Choose Duplicate.
- In the Select Template Type pop-up window, choose Invoice or Purchase Order. Then, click OK.
- Double-click on the template copy, and click the Manage Templates button in the Basic Customization window.
- Edit the template name in the Manage Templates window.
- Click OK twice.
Please see these sample screenshots for a visual guide:

Once done, you can delete the original template and check the column of the new one.
I'll be around if there's anything else you need. Thanks.