1. After uploading the modified trade agreement template a line level filter is applied, on the Journal Lines and trade agreement, the third lines will show up when you choose only one line. If you choose all lines, it will be grayed out.
2. However, after downloading the file, all data will be included in the excel file, not missing, just filtering the line that you choose in the 1^st step. Kindly check the result when I clear all the filter:

So the expectation is system can allow to choose all the lines on Journal Lines and trade agreement page, then filter them all in Office ad-on, not only one line.

The reproduce step as below:

• Create new Trade agreement journals ad Pric with the default relation as Price (purch.) Click on Line
• .Create 2 lines of relation for 2 items 4410 and 1000, then Save
• Choose both lines.
• Navigate to Open in Microsoft Office, then choose Export to excel – Trade agreement journal lines
• After download the file, open it:
• Remove or add additional fields to the template using the Design button.
• Save the file on your computer, giving an identifiable name
• Go to Organisation administration > Setup > Office integration > Document template
• Select the New button, then select Browse and select the file saved in step
• Ensure the following check boxes have been selected for the uploaded file
• Go to Procurement and sourcing > Prices and discounts > Trade agreement journals
• Select the same trade agreement and then the Lines button.
• Open the trade agreement in excel using the updated template.